CN114269412A - Tube inspection system and method - Google Patents

Abstract

An apparatus may include: a processing circuit; a humidifier configured to humidify the breathable gas; an air delivery tube configured to deliver the humidified breathable gas to a patient interface, the air delivery tube including a heating element, a sensor configured to measure a characteristic of the breathable gas, and a connector having a plurality of electrical tube contacts, at least a portion of which are coupled to the heating element and the sensor; and a contact assembly comprising a plurality of electrical device contacts configured to electrically couple the plurality of electrical tube contacts to the processing circuit. The processing circuit may be configured to determine the type of air delivery tube coupled to the humidifier based on (1) which electrical device contacts are coupled to the heating element and/or sensor, and/or (2) electrical characteristics measured via one or more electrical device contacts.

Description

Tube inspection system and method

1 cross reference to related applications

This application claims the benefit of U.S. provisional application No. 62/868,674 filed on 28.6.2019, which is incorporated herein by reference in its entirety. This application is related to U.S. provisional application No. 62/835,094 filed on 17.4.2019, the contents of which are incorporated herein by reference in their entirety.

2 background of the invention

2.1 technical field

The present technology relates to one or more of screening, diagnosis, monitoring, treatment, prevention, and amelioration of respiratory-related disorders. The present technology also relates to medical devices or apparatuses and uses thereof, and more particularly to methods and systems for identifying the type of device (e.g., the type of air delivery tube) coupled to an apparatus configured to provide a flow of breathable gas.

2.2 description of the related art

2.2.1 human respiratory System and diseases thereof

The respiratory system of the human body promotes gas exchange. The nose and mouth form the entrance to the patient's airways.

The airway includes a series of branch tubes that become narrower, shorter, and more numerous as the branch tubes penetrate deeper into the lungs. The main function of the lungs is gas exchange, allowing oxygen to move from the inhaled air into the venous blood and carbon dioxide to move in the opposite direction. The trachea is divided into left and right main bronchi, which eventually subdivide into terminal bronchioles. The bronchi constitute the conducting airways, but do not participate in gas exchange. Further branches of the airway lead to the respiratory bronchioles and ultimately to the alveoli. The alveolar region of the lung is the region where gas exchange occurs and is called the respiratory region. See "Respiratory Physiology (Respiratory Physiology)" published by John b.west, Lippincott Williams & Wilkins in 2012, 9 th edition.

There are a range of respiratory diseases. Certain diseases may be characterized by specific events, such as apnea, hypopnea, and hyperpnea.

Examples of respiratory disorders include Obstructive Sleep Apnea (OSA), cheyne-stokes respiration (CSR), respiratory insufficiency, Obesity Hyperventilation Syndrome (OHS), Chronic Obstructive Pulmonary Disease (COPD), neuromuscular disease (NMD), and chest wall disorders.

Obstructive Sleep Apnea (OSA) is a form of Sleep Disordered Breathing (SDB) characterized by events that include occlusion or obstruction of the upper airway during sleep. It is caused by a combination of abnormally small upper airways and normal loss of muscle tone in the tongue, soft palate and posterior oropharyngeal wall regions during sleep. This condition causes the affected patient to stop breathing, typically for a period of 30 to 120 seconds, sometimes 200 to 300 times per night. This often leads to excessive daytime sleepiness and can lead to cardiovascular disease and brain damage. Syndrome is a common disease, especially in middle-aged overweight men, but the affected person may not be aware of this problem. See U.S. Pat. No. 4,944,310 (Sullivan).

Tidal breathing (CSR) is another form of sleep disordered breathing. CSR is a disorder of the patient's respiratory controller, in which there are rhythmic alternating periods of hyperventilation called CSR cycles. CSR is characterized by repeated deoxygenation and reoxidation of arterial blood. CSR may be harmful due to repetitive hypoxia. In some patients, CSR is associated with repeated arousals from sleep, which results in severe sleep disruption, increased sympathetic activity, and increased afterload. See U.S. Pat. No. 6,532,959 (Berthon-Jones).

Respiratory failure is a covered term for respiratory diseases, where the lungs are unable to inhale enough oxygen or exhale enough CO₂To meet the needs of the patient. Respiratory failure may encompass some or all of the following diseases.

Patients with respiratory insufficiency, a form of respiratory failure, may experience abnormal shortness of breath while exercising.

Obesity Hyperventilation Syndrome (OHS) is defined as a combination of severe obesity and chronic hypercapnia while awake, with no other known causes of hypoventilation. Symptoms include dyspnea, morning headache, and excessive daytime sleepiness.

Chronic Obstructive Pulmonary Disease (COPD) encompasses any one of a group of lower airway diseases with certain common features. These include increased resistance to air movement, prolonged expiratory phase of breathing, and loss of normal elasticity of the lungs. Examples of COPD are emphysema and chronic bronchitis. COPD is caused by chronic smoking (a major risk factor), occupational exposure, air pollution and genetic factors. Symptoms include: effort dyspnea, chronic cough, and sputum production.

Neuromuscular disease (NMD) is a broad term that encompasses many diseases and ailments that impair muscle function either directly through intrinsic muscle pathology or indirectly through neuropathology. Some NMD patients are characterized by progressive muscle injury, which results in loss of walking ability, wheelchair occupancy, dysphagia, respiratory muscle weakness, and ultimately death from respiratory failure. Neuromuscular diseases can be divided into rapid and slow progression: (i) rapidly progressive disease: characterized by muscle damage that worsens over months and leads to death within a few years (e.g., Amyotrophic Lateral Sclerosis (ALS) and Duchenne Muscular Dystrophy (DMD) in adolescents, (ii) variable or slowly progressive disease characterized by muscle damage that worsens over years and only slightly shortens the life expectancy (e.g., limb-girdle, facioscapulohumeral, and tonic muscular dystrophy) symptoms of respiratory failure of NMD include increasing general weakness, dysphagia, dyspnea during exercise and rest, fatigue, lethargy, early morning pain, and difficulty concentrating and changing mood.

Chest wall disease is a group of thoracic deformities that result in inefficient coupling between the respiratory muscles and the thorax. These diseases are often characterized by restrictive defects and have the potential for long-term hypercapnic respiratory failure. Scoliosis and/or scoliosis can cause severe respiratory failure. Symptoms of respiratory failure include: dyspnea during exercise, peripheral edema, orthopnea, repeated chest infections, morning headaches, fatigue, poor sleep quality, and poor appetite.

A range of treatments have been used to treat or ameliorate such disorders. In addition, other healthy individuals may utilize such treatments to prevent the development of respiratory disorders. However, these have a number of disadvantages.

2.2.2 treatment

Various respiratory therapies, such as Continuous Positive Airway Pressure (CPAP) therapy, non-invasive ventilation (NIV), Invasive Ventilation (IV), and High Flow Therapy (HFT), have been used to treat one or more of the above-mentioned respiratory disorders.

2.2.2.1 respiratory pressure therapy

Respiratory pressure therapy is the application of supplying air to the entrance of the airway at a controlled target pressure that is nominally positive relative to atmosphere throughout the patient's respiratory cycle (as opposed to negative pressure therapy such as a canister ventilator or sternocoptera).

Continuous Positive Airway Pressure (CPAP) therapy has been used to treat Obstructive Sleep Apnea (OSA). The mechanism of action is that continuous positive airway pressure acts as a pneumatic splint and may prevent upper airway occlusion, such as by pushing the soft palate and tongue forward and away from the posterior oropharyngeal wall. Treatment of OSA with CPAP treatment may be voluntary, so if the patient finds the means for providing such treatment to be: any one or more of uncomfortable, difficult to use, expensive, and unsightly, the patient may choose not to comply with the treatment.

Non-invasive ventilation (NIV) provides ventilatory support to a patient through the upper airway to assist the patient in breathing and/or maintain adequate oxygen levels in the body by performing some or all of the work of breathing. Ventilation support is provided via a non-invasive patient interface. NIV has been used to treat CSR and respiratory failure, such as OHS, COPD, NMD and chest wall disease forms. In some forms, the comfort and effectiveness of these treatments may be improved.

non-Invasive Ventilation (IV) provides ventilatory support for patients who cannot breathe effectively on their own, and may be provided using an tracheostomy tube. In some forms, the comfort and effectiveness of these treatments may be improved.

2.2.2.2 flow therapy

Not all respiratory therapies are intended to deliver a prescribed therapeutic pressure. Some respiratory therapies aim to deliver a prescribed respiratory volume by delivering an inspiratory flow profile (possibly superimposed on a positive baseline pressure) over a target duration. In other cases, the interface to the patient's airway is "open" (unsealed) and respiratory therapy may supplement the flow of regulated or enriched gas only to the patient's own spontaneous breathing. In one example, High Flow Therapy (HFT) is the provision of a continuous, heated, humidified flow of air to the entrance of the airway through an unsealed or open patient interface to maintain a substantially constant "therapeutic flow" throughout the respiratory cycle. The treatment flow is nominally set to exceed the patient's peak inspiratory flow. HFTs have been used to treat OSA, CSR, respiratory failure, COPD and other respiratory disorders. One mechanism of action is the high flow of air at the entrance to the airway by flushing or flushing exhaled CO from the patient's anatomical dead space₂To improve the aeration efficiency. Therefore, HFT is sometimes referred to as Dead Space Therapy (DST). Other benefits may include elevated warmth and humidification (which may be beneficial for secretion management) and the possibility of moderate elevation of airway pressure. As an alternative to a constant flow, the therapeutic flow may follow a curve that varies with the respiratory cycle.

Another form of ambulatory therapy is long-term oxygen therapy (LTOT) or supplemental oxygen therapy. A physician may prescribe that a continuous flow of oxygen-enriched gas is delivered to the airway of a patient at a particular oxygen concentration (from 21% to 100% of the oxygen fraction in ambient air), at a particular flow rate (e.g., 1 Liter Per Minute (LPM), 2LPM, 3LPM, etc.).

2.2.2.3 supplement of oxygen

For some patients, oxygen therapy may be combined with respiratory pressure therapy or HFT by adding supplemental oxygen to the pressurized gas stream. When oxygen is added to respiratory pressure therapy, this is referred to as oxygen-supplemented RPT. When oxygen is added to HFT, the resulting therapy is referred to as HFT with supplemental oxygen.

2.2.3 respiratory therapy System

These respiratory therapies may be provided by a respiratory therapy system or device. Such systems and devices may also be used to screen, diagnose, or monitor a condition without treating it.

The respiratory therapy system may include a respiratory pressure therapy device (RPT device), an air circuit, a humidifier, a patient interface, an oxygen source, and data management.

Another form of treatment system is a mandibular repositioning device.

2.2.3.1 patient interface

The patient interface may be used to couple the breathing apparatus to its wearer, for example by providing a flow of air to an inlet of the airway. The air flow may be provided into the patient's nose and/or mouth via a mask, into the mouth via a tube, or into the patient's trachea via a tracheostomy tube. Depending on the therapy to be applied, the patient interface may form a seal with an area, such as a patient's face, to facilitate the gas to be at a pressure sufficiently different from ambient pressure (e.g., about 10cmH relative to ambient pressure)₂Positive pressure of O) to effect treatment. For other forms of therapy, such as oxygen delivery, the patient interface may not include sufficient material to facilitate approximately 10cmH₂A supply of gas at positive pressure of O is delivered to the seal of the airway. For flow therapies such as nasal HFT, the patient interface is configured to insufflate the nares, but specifically avoid a complete seal. One example of such a patient interface is a nasal cannula.

Some other mask systems may not be functionally suitable for use in the field. For example, a purely decorative mask may not be able to maintain proper pressure. A mask system for underwater swimming or diving may be configured to prevent the ingress of higher pressure water from the outside, but not to maintain the internal air at a pressure above ambient pressure.

Some masks may be clinically disadvantageous to the present technique, for example if they block airflow through the nose and only allow it to pass through the mouth.

Some masks may be uncomfortable or impractical for the present technique if it is desired for the patient to insert a portion of the mask structure in their mouth to create and maintain a seal with their lips.

Some masks may be impractical to use while sleeping, for example, when lying on their sides in a bed and having their heads sleeping on a pillow.

The design of patient interfaces presents a number of challenges. The face has a complex three-dimensional shape. The size and shape of the nose and head vary greatly from individual to individual. Since the head comprises bone, cartilage and soft tissue, different regions of the face respond differently to mechanical forces. The jaw or mandible may move relative to other bones of the skull. The entire head can be moved during the respiratory therapy.

As a result of these challenges, some masks suffer from one or more of raised, aesthetically undesirable, expensive, poorly fitting, difficult to use, and uncomfortable issues, particularly when worn for extended periods of time or when the patient is unfamiliar with the system. A wrong size mask may lead to reduced compliance, reduced comfort and poor patient outcomes. Masks designed only for pilots, masks designed as part of personal protective equipment (e.g., filtering masks), SCUBA masks, or masks for administration of anesthetic agents are tolerable for their original use, but nonetheless such masks may be undesirably uncomfortable to wear over extended periods of time (e.g., hours). This discomfort may lead to reduced patient compliance with the treatment. This is especially true if the mask is worn during sleep.

CPAP therapy is highly effective for treating certain respiratory diseases, provided that the patient is compliant with the therapy. Patients may not comply with the treatment if the mask is uncomfortable or difficult to use. Because patients are often advised to wash their masks on a regular basis, if the masks are difficult to clean (e.g., difficult to assemble or disassemble), the patients may not be able to clean their masks, and this may affect patient compliance.

While masks designed for use in treating sleep disordered breathing may be unsuitable for use in other applications (e.g., navigators), masks designed for use in treating sleep disordered breathing may be suitable for use in other applications.

For these reasons, patient interfaces for delivering CPAP during sleep form a different field.

Respiratory Pressure Therapy (RPT) device

Respiratory Pressure Therapy (RPT) devices may be used alone or as part of a system to deliver one or more of the various therapies described above, such as by operating the device to generate a flow of air for delivery to an airway interface. The gas flow may be pressure controlled (for respiratory pressure therapy) or flow controlled (for flow therapy such as HFT). Thus, the RPT device may also be used as a flow treatment device. Examples of RPT devices include CPAP devices and ventilators.

Air pressure generators are known in a variety of applications, such as industrial scale ventilation systems. However, air pressure generators for medical applications have specific requirements that are not met by more general air pressure generators, such as reliability, size and weight requirements of medical devices. Furthermore, even devices designed for medical treatment may have disadvantages associated with one or more of the following: comfort, noise, ease of use, efficacy, size, weight, manufacturability, cost, and reliability.

One example of a particular requirement of some RPT devices is noise.

Existing RPT devices (one sample only, using the test method specified in ISO 3744 in CPAP mode at 10cmH₂Measured at O) noise output level.

RPT device name	A-weighted sound pressure level dB (A)	Year (about)
			C-Series TangoTM	31.9	2007
C-Series Tango with humidifierTM	33.1	2007
			S8 EscapeTM II	30.5	2005
With H4iTMHumidifier S8 EscapeTM II	31.1	2005
			S9 AutoSetTM	26.5	2010
S9 AutoSet with H5i humidifierTM	28.6	2010

One known RPT device for treating sleep disordered breathing is the S9 sleep therapy system manufactured by ResMed Limited. Another example of an RPT device is a ventilator. Respirators, e.g. ResMed Stellar for adult and pediatric respirators^TMA series of patients may be provided with invasive and non-invasive independent ventilatory support for the treatment of a variety of conditions, such as but not limited to NMD, OHS and COPD.

Treated ResMed Elis é e^TM150 ventilator and treated ResMed VS III^TMThe ventilator may provide invasive and non-invasive dependencies suitable for adult or pediatric patientsVentilatory support to treat a variety of conditions. These ventilators provide volume and pressure ventilation modes with either a single-limb circuit or a dual-limb circuit. RPT devices typically include a pressure generator, such as a motor-driven blower or a compressed gas reservoir, and are configured to supply a flow of air to the airway of a patient. In some cases, the flow of air may be provided to the airway of the patient at a positive pressure. The outlet of the RPT device is connected to a patient interface such as those described above via an air circuit.

The designer of the device may be presented with an unlimited number of choices to make. Design criteria are often conflicting, meaning that certain design choices are far from routine or unavoidable. Furthermore, certain aspects of comfort and efficacy may be highly sensitive to subtle changes in one or more parameters.

2.2.3.2 air circuit

The air circuit is a conduit or tube constructed and arranged to allow, in use, an air flow to travel between two components of a respiratory therapy system, such as an RPT device and a patient interface. In some cases, there may be separate branches of the air circuit for inhalation and exhalation. In other cases, a single branched air circuit is used for inspiration and expiration.

2.2.3.3 humidifier

Delivering a flow of air without humidification may result in airway drying. The use of a humidifier with an RPT device and a patient interface produces humidified gas that minimizes drying of the nasal mucosa and increases patient airway comfort. Furthermore, in colder climates, warm air, which is typically applied to the facial area in and around the patient interface, is more comfortable than cold air. Thus, humidifiers generally have the ability to heat an air stream as well as humidify the air stream.

Many manual humidification devices and systems are known, however they do not meet the special requirements of medical humidifiers.

Medical humidifiers are used to increase the humidity and/or temperature of the air flow relative to the ambient air when needed, typically in a place where the patient is asleep or resting (e.g., in a hospital). Medical humidifiers for bedside placement may be small. Medical humidifiers may be configured to humidify and/or heat only the flow of air delivered to a patient, without humidifying and/or heating the patient's surroundings. For example, room-based systems (e.g., sauna, air conditioner, or evaporative cooler) may also humidify the air inhaled by the patient, however these systems also humidify and/or heat the entire room, which may cause discomfort to the occupants. In addition, medical humidifiers may have stricter safety constraints than industrial humidifiers.

While many medical humidifiers are known, they may have one or more drawbacks. Some medical humidifiers may provide inadequate humidification, and some patients may be difficult or inconvenient to use.

2.2.3.4 oxygen source

Experts in the field have recognized that exercise on respiratory failure patients provides long-term benefits, which slow the progression of the disease, improve the quality of life and extend the life span of the patient. However, most stationary forms of exercise such as treadmills and stationary bicycles are too strenuous for these patients. As a result, the need for mobility has long been recognized. Until recently, this fluidity was promoted by the use of small compressed oxygen tanks or cylinders mounted on carts with trolley wheels. The disadvantage of these tanks is that they contain a limited amount of oxygen and are heavy, weighing about 50 pounds when installed.

Oxygen concentrators have been used for about 50 years to provide oxygen for respiratory therapy. Conventional oxygen concentrators are bulky and heavy, making ordinary flow activity difficult and impractical. Recently, companies that manufacture large stationary oxygen concentrators have begun to develop Portable Oxygen Concentrators (POCs). The advantage of POC is that they can generate a theoretically unlimited supply of oxygen. In order to make these devices less mobile, it is necessary that the various systems for producing the oxygen-enriched gas be condensed. POC seeks to utilize the oxygen it produces as efficiently as possible to minimize weight, size and power consumption. This may be achieved by delivering oxygen in a series of pulses or "bolus", each dose (bolus) being timed to coincide with the start of inspiration. This mode of treatment is known as pulsed or on-demand (oxygen) delivery (POD), as opposed to conventional continuous flow delivery, which is more suitable for stationary oxygen concentrators.

2.2.3.5 data management

There may be clinical reasons for obtaining data to determine whether a patient prescribed respiratory therapy has "complied with," e.g., the patient has used their RPT device according to one or more "compliance rules. One example of a compliance rule for CPAP therapy is to require a patient to use an RPT device overnight for at least 4 hours for at least 21 out of 30 consecutive days in order to be considered compliant. To determine patient compliance, a provider of the RPT device (e.g., a healthcare provider) may manually obtain data describing the treatment of a patient using the RPT device, calculate usage over a predetermined period of time, and compare to compliance rules. Once the healthcare provider has determined that the patient has used their RPT device according to the compliance rules, the healthcare provider may notify the third party that the patient is compliant.

There may be other aspects of patient treatment that would benefit from communication of treatment data to a third party or external system.

Existing processes for communicating and managing such data can be one or more of expensive, time consuming, and error prone.

2.2.3.6 mandible reduction

Mandibular Repositioning Devices (MRDs) or Mandibular Advancement Devices (MADs) are one of the treatment options for sleep apnea and snoring. It is an adjustable oral appliance available from dentists or other suppliers that holds the mandible (mandible) in a forward position during sleep. MRDs are removable devices that patients insert into their mouths before sleeping and remove after sleeping. Therefore, MRDs are not designed to be worn all the time. MRDs can be custom made or produced in standard form and include bite impression portions designed to allow fitting to a patient's teeth. This mechanical protrusion of the mandible enlarges the space behind the tongue, exerting tension on the pharyngeal wall to reduce collapse of the airway and reduce palate vibration.

In some examples, the mandibular advancement device may include an upper splint for engaging or fitting over the teeth of the maxilla or the maxilla and a lower splint for engaging or fitting over the teeth of the maxilla or the mandible. The upper and lower clamping plates are laterally connected together by a pair of connecting rods. The pair of connecting rods are symmetrically fixed on the upper clamping plate and the lower clamping plate.

In this design, the length of the connecting rod is selected so that the mandible remains in an advanced position when the MRD is placed in the patient's mouth. The length of the connecting rod can be adjusted to change the level of protrusion of the mandible. The dentist can determine the level of protrusion of the mandible, which will determine the length of the connecting rod.

Some MRDs are configured to push the mandible forward relative to the maxilla, while others (e.g., ResMed Narval CC)^TMMRD) is designed to hold the mandible in an anterior position. The device also reduces or minimizes dental and temporomandibular joint (TMJ) side effects. Thus, it is configured to minimize or prevent any movement of one or more teeth.

2.2.4 screening, diagnostic and monitoring System

Polysomnography (PSG) is a conventional system for diagnosing and monitoring cardiopulmonary disease, and typically involves a clinical specialist to apply the system. PSG typically involves placing 15 to 20 contact sensors on a patient to record various body signals, such as electroencephalogram (EEG), Electrocardiogram (ECG), Electrooculogram (EOG), Electromyogram (EMG), and the like. PSG of sleep disordered breathing involves clinically observing the patient for two nights, a pure diagnosis for one night and a clinician titrating the treatment parameters for the second night. Thus, PSG is expensive and inconvenient. In particular, it is not suitable for home screening/diagnosis/monitoring of sleep disordered breathing.

Screening and diagnosis generally describe the identification of a disorder from its signs and symptoms. Screening typically gives a true/false result indicating whether the patient's SDB is severe enough to warrant further study, while diagnosis can yield clinically actionable information. Screening and diagnosis tend to be a one-time process, while monitoring disease progression may continue indefinitely. Some screening/diagnostic systems are only suitable for screening/diagnosis, while some may also be used for monitoring.

A clinical expert may be able to adequately screen, diagnose, or monitor patients based on visually observed PSG signals. However, there are situations where a clinical expert may not be available or may not be affordable. Different clinical experts may not agree on the patient's condition. Furthermore, a given clinical expert may apply different criteria at different times.

Disclosure of the invention

The present technology is directed to providing a medical device for screening, diagnosing, monitoring, ameliorating, treating, or preventing a respiratory disorder that has one or more of improved comfort, cost, efficacy, ease of use, and manufacturability.

A first aspect of the present technology relates to a device for screening, diagnosing, monitoring, ameliorating, treating or preventing a respiratory disorder.

Another aspect of the technology relates to methods for screening, diagnosing, monitoring, ameliorating, treating, or preventing a respiratory disorder.

One aspect of certain forms of the present technology is to provide methods and/or devices for improving patient compliance with respiratory therapy.

One form of the present technique includes identifying the type of air delivery tube connected to the device so that the operation of the device can be optimized for the identified air delivery tube.

Another aspect of the technology relates to a processing circuit configured to identify a type of air delivery tube coupled to a device for humidifying a flow of breathable gas based on electrical contacts of the device being used by contacts of the air delivery tube.

Another aspect of the technology relates to a processing circuit configured to identify a type of air delivery tube coupled to an apparatus for humidifying a flow of breathable gas based on a measured characteristic of a passive or active circuit component in the air delivery tube.

Another aspect of the technology relates to a processing circuit configured to identify a type of air delivery tube coupled to a device for humidifying a flow of breathable gas based on measuring a characteristic of a circuit in the air delivery tube that is not part of a sensing circuit for measuring a temperature in the air delivery tube. The characteristics of the circuit may include the presence or absence of a resistance value on one or more electrical connections of the air delivery tube.

Another aspect of the technology relates to a respiratory therapy device that includes a processing circuit configured to identify a type of air delivery tube coupled to a humidifier and/or flow generator of the device based on measured circuit characteristics of the air delivery tube that are not part of a sensing circuit for measuring a temperature in the air delivery tube. The characteristics of the circuit may include the presence or absence of connections and/or resistance values on one or more electrical connections of the air delivery tubing.

Another aspect of the technology relates to an apparatus comprising a processing circuit; a humidifier configured to humidify the breathable gas; an air delivery tube configured to deliver the humidified breathable gas to a patient interface, the air delivery tube including a heating element, a sensor configured to measure a characteristic of the breathable gas, and a connector having a plurality of electrical tube contacts, at least a portion of which are coupled to the heating element and the sensor; and a contact assembly comprising a plurality of electrical device contacts configured to electrically couple the plurality of electrical tube contacts to the processing circuit. The processing circuit may be configured to determine the type of air delivery tube coupled to the humidifier based on (1) which electrical device contacts are coupled to the heating element and/or sensor, and/or (2) electrical characteristics measured via one or more electrical device contacts.

Another aspect of the technology relates to an apparatus for humidifying a flow of breathable gas, comprising: a processing circuit; a humidifier configured to humidify the breathable gas; an air delivery tube configured to deliver the humidified breathable gas to a patient interface, the air delivery tube including one or more heating elements extending along at least a portion of a length of the air delivery tube, a sensor configured to measure a characteristic of the humidified breathable gas in the air delivery tube, and a connector having a plurality of electrical tube contacts; and a contact assembly comprising a plurality of electrical device contacts configured to electrically couple the plurality of electrical tube contacts to the processing circuitry, wherein the one or more heating elements and the sensor are coupled to the electrical tube contacts, and the electrical tube contacts are adapted to electrically engage only a portion of the electrical device contacts in an operational configuration of the device.

In an example of the foregoing aspect: (a) the processing circuitry may be configured to control operation of the one or more heating elements and the humidifier based on signals received from the sensor, and determine a type of air delivery tube coupled to the device based on which electrical device contacts of the contact assembly are coupled to the electrical tube contacts in an operational configuration of the device; (b) the processing circuitry may be configured to determine a type of air delivery tube coupled to the device based on which electrical device contacts of the contact assembly are coupled to the electrical tube contacts in an operational configuration of the device; (c) the processing circuitry may be configured to control operation of the one or more heating elements and/or the humidifier based on the determined type of air delivery tube; (d) the processing circuitry may be configured to determine a type of air delivery tube coupled to the device based on a lack of connection to the heating element and/or sensor through one or more electrical device contacts; (e) the contact assembly may include only four electrical device contacts, a first pair of electrical device contacts configured to electrically couple to the one or more heating elements, and only one contact of a second pair of electrical device contacts configured to electrically couple to the sensor; (f) the processing circuitry may determine a type of air delivery tube coupled to the device based on which of the second pair of electrical device contacts is coupled to the sensor; (g) the contact assembly may include only four electrical device contacts, a first pair of the electrical device contacts configured to electrically couple to the one or more heating elements, and the processing circuit may be configured to determine that a first type of air delivery tube is coupled to the device when a first contact of a second pair of the electrical device contacts is not coupled to the sensor, and determine that a second type of air delivery tube is coupled to the device when a second contact of the second pair of the electrical device contacts is not coupled to the sensor; (h) the contact assembly may include only four electrical device contacts, and the air delivery tube may include only three electrical tube contacts configured to couple to the electrical device contacts; and/or (i) the processing circuitry may be configured to determine the type of air delivery tube coupled to the device based on which electrical device contact of the contact assembly is not coupled to the electrical tube contact.

Another aspect of the technology relates to an apparatus for humidifying a flow of breathable gas, comprising: a processing circuit; a humidifier configured to humidify the breathable gas; an air delivery tube configured to deliver humidified breathable gas to a patient interface, the air delivery tube including one or more heating elements extending along at least a portion of a length of the air delivery tube, a sensor configured to measure a characteristic of the breathable gas in the air delivery tube, and a connector having a plurality of electrical tube contacts; and a contact assembly comprising a plurality of electrical device contacts configured to electrically couple the plurality of electrical tube contacts to the processing circuitry in an operational configuration of the device, wherein the one or more heating elements and the sensor are coupled to a set of the electrical tube contacts configured to electrically couple to the corresponding electrical device contacts in an operational configuration of the device, and the processing circuitry is configured for determining a type of air delivery tube coupled to the device based on an electrical characteristic measured by the processing circuitry via another electrical device contact of the contact assembly.

In an example of the foregoing aspect: (a) the processing circuitry may be configured to control operation of the one or more heating elements and the humidifier based on signals received from the sensor; (b) the measured characteristic may include a voltage set based on a resistive element disposed in the air delivery tube and coupled to the another electrical device contact, and an electrical tube contact configured to electrically couple to a heating element; (c) the processing circuitry may be configured to determine that a first type of air delivery tube is coupled to the device when the measured characteristic indicates zero volts and that a second type of air delivery tube is coupled to the device when the measured characteristic indicates a voltage greater than zero; (d) the air delivery tube may include a resistor or shunt coupled between a contact of the set of electrical tube contacts and an electrical tube contact configured to electrically couple to the other electrical equipment contact; (e) the processing circuitry may be configured to control operation of the one or more heating elements and the humidifier based on the determined type of air delivery tube; and/or (f) the contact assembly may include only four electrical device contacts, and the air delivery tube includes only three electrical tube contacts configured to couple to the electrical device contacts.

Another aspect of the technology relates to a respiratory therapy apparatus comprising: a power source; a processing system; a pressure generator configured for generating a flow of breathable gas; a humidifier configured to store a supply of water to humidify the breathable gas and comprising a first heating element configured to heat the supply of water; an air delivery tube configured to deliver a humidified flow of breathable gas to a patient, the air delivery tube including a second heating element configured to heat the humidified breathable gas in the air delivery tube and a thermistor configured to generate a temperature signal indicative of a temperature of the humidified breathable gas in the air delivery tube; a converter configured to generate a flow signal representative of a characteristic of the flow of breathable gas; and a contact assembly configured to mechanically couple the air delivery tube to the humidifier and electrically couple a plurality of main contacts coupled to the processing system to a plurality of tube contacts coupled to the second heating element and the thermistor, wherein in an operating configuration of the respiratory therapy apparatus, only a portion of the main contacts are coupled to respective tube contacts. The processing system may be configured to: determining which of the main contacts is coupled to the second heating element and the thermistor via the tube contact based on signal values received from the one or more main contacts; determining a type of air delivery tube coupled to the humidifier based on the determination of which main contact is coupled to the second heating element and the thermistor; and determining (1) a first control signal for controlling the first heating element, (2) a second control signal for controlling the second heating element, and (3) a third control signal for controlling the pressure generator based on the determined tube type, flow signal, and temperature signal.

In an example of the foregoing aspect: the contact assembly includes two main contacts configured to electrically couple to two tube contacts coupled to the second heating element and two additional main contacts configured to couple to two additional tube contacts, only one of the two additional tube contacts being coupled to the thermistor, and the processing system is configured to determine a type of air delivery tube coupled to the humidifier based on which of the two additional main contacts is coupled to the thermistor via the tube contact.

Another aspect of one form of the present technology is a patient interface that is molded or otherwise constructed to have a perimeter shape that is complementary to the perimeter shape of the intended wearer.

One aspect of one form of the present technology is a method of manufacturing a device.

One aspect of some forms of the present technology is an easy-to-use medical device, for example, by a person without medical training, by a person with limited dexterity, vision, or by a person with limited experience in using medical devices of this type.

One aspect of one form of the present technology is a portable RPT device that may be carried by a person (e.g., in a person's home).

One aspect of one form of the present technology is a patient interface that can be rinsed in the patient's home, e.g., in soapy water, without the need for specialized cleaning equipment. One aspect of one form of the present technology is a humidifier tub that can be washed in the patient's home, e.g., in soapy water, without the need for specialized cleaning equipment.

The described methods, systems, apparatuses, and devices may be implemented to improve the functionality of a processor, such as a processor of a special purpose computer, respiratory monitor, and/or respiratory therapy device. Furthermore, the described methods, systems, devices, and apparatus may provide improvements in the art of automated management, monitoring, and/or treatment of respiratory conditions, including, for example, sleep disordered breathing.

Of course, some of these aspects may form a sub-aspect of the present technology. Moreover, the sub-aspects and/or various aspects of the aspects may be combined in various ways, and form further aspects or sub-aspects of the technology.

Other features of the present technology will become apparent in view of the information contained in the following detailed description, abstract, drawings, and claims.

4 description of the drawings

The present technology is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:

4.1 respiratory therapy System

Fig. 1 shows a system comprising a patient 1000 wearing a patient interface 3000 in the manner of a nasal pillow receiving a supply of air at positive pressure from an RPT device 4000. Air from the RPT device 4000 is conditioned in the humidifier 5000 and delivered to the patient 1000 along an air circuit 4170. A bed partner 1100 is also shown. The patient sleeps in a supine sleeping position.

Fig. 2 shows a system comprising a patient 1000 wearing a patient interface 3000 in the form of a nasal mask receiving a supply of air at positive pressure from an RPT device 4000. Air from the RPT device is humidified in humidifier 5000 and delivered to patient 1000 along air circuit 4170.

Fig. 3 shows a system comprising a patient 1000 wearing a patient interface 3000 in a full-face mask manner receiving a supply of air at positive pressure from an RPT device 4000. Air from the RPT device is humidified in humidifier 5000 and delivered to patient 1000 along air circuit 4170. The patient sleeps in the side sleeping position.

4.2RPT device

Fig. 4A illustrates an RPT device in accordance with one form of the present technique.

Fig. 4B is a schematic illustration of the pneumatic path of an RPT device in accordance with one form of the present technique. The upstream and downstream directions are indicated with reference to the blower and patient interface. The blower is defined upstream of the patient interface and the patient interface is defined downstream of the blower, regardless of the actual flow direction at any particular time. Items located in the pneumatic path between the blower and the patient interface are downstream of the blower and upstream of the patient interface.

Fig. 4C is a schematic diagram of electrical components of an RPT device in accordance with one form of the present technique.

Fig. 4D is a schematic diagram of an algorithm implemented in the RPT device in accordance with one form of the present technique.

Fig. 4E is a flow diagram illustrating a method performed by the therapy engine module of fig. 4D in accordance with one form of the present technique.

4.3 humidifier

Fig. 5A illustrates an isometric view of a humidifier in accordance with one form of the present technology.

Fig. 5B illustrates an isometric view of a humidifier in accordance with one form of the present technology, showing the humidifier reservoir 5110 removed from the humidifier reservoir base 5130.

Fig. 5C shows a schematic view of a humidifier in accordance with one form of the present technology.

4.4 tube type identification

FIG. 5D illustrates a schematic diagram of an air delivery tube including four wires connected to an RPT device, in accordance with one form of the present technique.

Fig. 5E shows a schematic diagram of an air delivery tube including three wires connected to an RPT device in accordance with one form of the present technique.

Fig. 5F shows a schematic diagram of an air delivery tube including three wires connected to an RPT device in accordance with another form of the present technique.

FIG. 5G shows a schematic diagram of an air delivery tube connected to an RPT device that includes a detection line for identifying a tube type, in accordance with one form of the present technique.

FIG. 5H shows a schematic diagram of an air delivery tube connected to an RPT device that includes a detection line for identifying a tube type, in accordance with one form of the present technique.

FIG. 5I illustrates an example heat pipe detection circuit in accordance with one form of the present technique.

FIG. 5J illustrates another example heat pipe detection circuit in accordance with one form of the present technique.

4.5 respiratory waveforms

Fig. 6A shows a model typical respiration waveform of a person while sleeping.

Fig. 6B shows selected polysomnography channels (pulse oximetry, flow, chest movement, and abdominal movement) of a patient during non-REM sleep breathing over a period of about ninety seconds under normal circumstances.

Figure 6C shows polysomnography of a patient before treatment.

Fig. 6D shows patient flow data for a series of completely obstructive apneas the patient is experiencing.

Figure 6E shows a scaled inspiratory portion of a breath in which the patient is experiencing low frequency inspiratory snoring.

Fig. 6F shows a scaled inspiratory portion of an example breath in which the patient is experiencing a flattened inspiratory flow limitation.

Fig. 6G shows a scaled inspiratory portion of a breath for which the patient is experiencing an example "tabletop" flattened inspiratory flow limitation.

Fig. 6H shows a scaled inspiratory portion of an example breath in which the patient is experiencing an "panda-ear" inspiratory flow limitation.

Fig. 6I shows a scaled inspiratory portion of an example breath in which the patient is experiencing a "chair" inspiratory flow limitation.

Fig. 6J shows a scaled inspiratory portion of an example breath in which the patient is experiencing a "reverse chair" inspiratory flow limitation.

Fig. 6K shows a scaled inspiratory portion of a breath for which the patient is experiencing an example "M-shaped" inspiratory flow limitation.

Fig. 6L shows a scaled inspiratory portion of a breath for which the patient is experiencing a severe "M-shaped" inspiratory flow limitation.

Fig. 6M shows patient data from a patient with tidal breathing.

Fig. 6N shows patient data for a patient with another example of cheyne-stokes respiration using the same three channels as in fig. 6M.

Detailed description of the preferred embodiments

Before the present technology is described in further detail, it is to be understood that this technology is not limited to the particular examples described herein, as the particular examples described herein may vary. It is also to be understood that the terminology used in the present disclosure is for the purpose of describing particular examples only and is not intended to be limiting.

The following description is provided in connection with various examples that may share one or more common features and/or characteristics. It should be understood that one or more features of any one example may be combined with one or more features of another example or other examples. Additionally, in any of the examples, any single feature or combination of features may constitute further examples.

5.1 treatment

In one form, the present technology includes a method for treating a respiratory disorder that includes applying positive pressure to an entrance to an airway of a patient 1000.

In some examples of the present technology, a supply of air at positive pressure is provided to the nasal passages of a patient via one or both nostrils.

In certain examples of the present technology, mouth breathing is defined, limited, or prevented.

5.2 respiratory therapy System

In one form, the present technology includes a respiratory therapy system for treating a respiratory disorder. The respiratory therapy system may include an RPT device 4000 for supplying a flow of air to a patient 1000 via an air circuit 4170 and a patient interface 3000 or 3800.

5.3 patient interface

The non-invasive patient interface 3000 according to one aspect of the present technique includes the following functional aspects: a seal forming structure 3100, a plenum chamber 3200, a positioning and stabilizing structure 3300, a vent 3400, a form of connection port 3600 for connection to an air circuit 4170, and a forehead support 3700. In some forms, the functional aspects may be provided by one or more physical components. In some forms, one physical component may provide one or more functional aspects. In use, the seal forming structure 3100 is arranged to surround an entrance to the airways of a patient in order to maintain a positive pressure at the entrance to the airways of the patient 1000. Thus, sealed patient interface 3000 is suitable for delivering positive pressure therapy.

Unsealed patient interfaces 3800 in the form of nasal cannulas include nasal inserts 3810a, 3810b that can deliver air to the respective nares of patient 1000 via respective apertures in their tips. Such nasal inserts typically do not form a seal with the inner or outer skin surfaces of the nares. Air may be delivered to the nasal inserts through one or more air supply lumens 3820a, 3820b coupled with the nasal cannula 3800. The lumens 3820a, 3820b lead from the nasal cannula 3800 to the respiratory therapy device via an air circuit. The unsealed patient interface 3800 is particularly suited for delivering flow therapies in which the RPT device generates a flow of air at a controlled flow rate rather than a controlled pressure. A "vent" at the unsealed patient interface 3800 is a passage between the ends of the pins 3810a and 3810b of the cannula 3800 to atmosphere via the patient's nares through which excess airflow escapes to the ambient environment.

If the patient interface is not able to comfortably deliver a minimum level of positive pressure to the airway, the patient interface may not be suitable for respiratory pressure therapy.

Patient interface 3000 according to one form of the present technique is constructed and arranged to be capable of at least 6cmH relative to the environment₂The positive pressure of O supplies air.

Patient interface 3000 according to one form of the present technique is constructed and arranged to be capable of operating at least 10cmH relative to the environment₂The positive pressure of O supplies air.

Patient interface 3000 according to one form of the present technique is constructed and arranged to be capable of operating at least 20cmH relative to the environment₂The positive pressure of O supplies air.

5.4RPT device

An RPT device 4000 in accordance with an aspect of the present technique includes mechanical, pneumatic, and/or electrical components and is configured to execute one or more algorithms 4300, such as any of all or a portion of the methods described herein. RPT device 4000 may be configured to generate a flow of air for delivery to the airway of a patient, e.g., for treating one or more respiratory conditions described elsewhere in this document.

In one form, the RPT device 4000 is constructed and arranged to be capable of delivering an air flow in the range of-20L/min to +150L/min while maintaining at least 6cmH₂O, or at least 10cmH₂O, or at least 20cmH₂Positive pressure of O.

The RPT device may have an outer housing 4010 formed in two parts: an upper portion 4012 and a lower portion 4014. In addition, the external housing 4010 can include one or more panels 4015. The RPT device 4000 comprises a chassis 4016 that supports one or more internal components of the RPT device 4000. The RPT device 4000 may include a handle 4018.

The pneumatic path of the RPT device 4000 may include one or more air path items, such as an inlet air filter 4112, an inlet muffler 4122, a pressure generator 4140 (e.g., blower 4142) capable of positive pressure supply of air, an outlet muffler 4124, and one or more transducers 4270, such as a pressure sensor 4272 and a flow sensor 4274.

One or more air path items may be located within a removable unitary structure that will be referred to as a pneumatic block 4020. A pneumatic block 4020 may be located within the outer housing 4010. In one form, the pneumatic block 4020 is supported by the chassis 4016 or is formed as part of the chassis 4016.

The RPT device 4000 may have a power supply 4210, one or more input devices 4220, a central controller 4230, a therapy device controller 4240, a pressure generator 4140, one or more protection circuits 4250, a memory 4260, a converter 4270, a data communication interface 4280, and one or more output devices 4290. The electrical components 4200 may be mounted on a single Printed Circuit Board Assembly (PCBA) 4202. In an alternative form, the RPT device 4000 may include more than one PCBA 4202.

5.4.1 RPT device mechanical & pneumatic Components

The RPT device may include one or more of the following components in a single integral unit. In the alternative, one or more of the following components may be positioned as respective independent units.

5.4.1.1 air filter

One form of RPT device in accordance with the present technology may include one air filter 4110, or a plurality of air filters 4110.

In one form, inlet air filter 4112 is located at the beginning of the pneumatic path upstream of pressure generator 4140.

In one form, an outlet air filter 4114, e.g., an antimicrobial filter, is positioned between the outlet of the pneumatic block 4020 and the patient interface 3000 or 3800.

5.4.1.2 silencer

An RPT device in accordance with one form of the present technique may include a muffler 4120, or a plurality of mufflers 4120.

In one form of the present technique, inlet muffler 4122 is located in the pneumatic path upstream of pressure generator 4140.

In one form of the present technology, the outlet muffler 4124 is located in the pneumatic path between the pressure generator 4140 and the patient interface 3000 or 3800.

5.4.1.3 pressure generator

In one form of the present technique, the pressure generator 4140 for generating a positive pressure air flow or air supply is a controllable blower 4142. For example, the blower 4142 may include a brushless DC motor 4144 having one or more impellers. The impeller may be located in a volute. The blower can be, for example, at a rate of up to about 120 liters/minute, at about 4cmH₂O to about 20cmH₂Under positive pressure in the O range, or up to about 30cmH when delivering respiratory pressure therapy₂Other forms of O deliver air supply. The blower may be as described in any of the following patents or patent applications, the contents of which are incorporated herein by reference in their entirety: U.S. patent No. 7,866,944; U.S. patent No. 8,638,014; U.S. patent No. 8,636,479; and PCT patent application publication No. WO 2013/020167.

The pressure generator 4140 is under the control of the treatment device controller 4240.

In other forms, pressure generator 4140 may be a piston driven pump, a pressure regulator connected to a high pressure source (e.g., a compressed air reservoir), or a bellows.

5.4.1.4 converter

The converter may be internal to the RPT device or external to the RPT device. The external transducer may be located on or form part of an air circuit (e.g., a patient interface), for example. The external transducer may be in the form of a non-contact sensor, such as a doppler radar motion sensor that transmits or transfers data to the RPT device.

In one form of the present technology, one or more transducers 4270 are located upstream and/or downstream of pressure generator 4140. The one or more transducers 4270 may be constructed and arranged to generate a signal indicative of a characteristic of the air flow (e.g., flow, pressure, or temperature) at the point in the pneumatic path.

In one form of the present technology, one or more transducers 4270 may be located near patient interface 3000 or 3800.

In one form, the signal from the transducer 4270 may be filtered, such as by low pass, high pass, or band pass filtering.

5.4.1.4.1 flow sensor

The flow sensor 4274 in accordance with the present technology may be based on a differential pressure transducer, such as the SDP600 series differential pressure transducer from sensioron.

In one form, a signal generated by the flow sensor 4274 and indicative of flow is received by the central controller 4230.

5.4.1.4.2 pressure sensor

A pressure sensor 4272 in accordance with the present techniques is positioned in fluid communication with the pneumatic path. An example of a suitable pressure sensor is a transducer from the HONEYWELL ASDX family. Another suitable pressure sensor is the NPA series of transducers from GENERAL ELECTRIC.

In one form, the signal generated by pressure sensor 4272 is received by central controller 4230.

5.4.1.4.3 Motor speed changer

In one form of the present technique, the motor speed converter 4276 is used to determine the rotational speed of the motor 4144 and/or the blower 4142. The motor speed signal from the motor speed converter 4276 may be provided to the treatment device controller 4240. The motor speed converter 4276 may be, for example, a speed sensor, such as a hall effect sensor.

5.4.1.5 spill-proof valve

In one form of the present technology, an anti-spill back valve 4160 is positioned between the humidifier 5000 and the pneumatic block 4020. The anti-spill back valve is constructed and arranged to reduce the risk of water flowing upstream from the humidifier 5000 to, for example, the motor 4144.

5.4.2RPT device Electrical Components

5.4.2.1 electric source

The power supply 4210 may be located inside or outside the housing 4010 of the RPT device 4000.

In one form of the present technology, the power supply 4210 provides power only to the RPT device 4000. In another form of the present technology, the power supply 4210 provides power to both the RPT device 4000 and the humidifier 5000.

5.4.2.2 input device

In one form of the present technology, the RPT device 4000 includes one or more input devices 4220 in the form of buttons, switches, or dials to allow a person to interact with the device. The buttons, switches or dials may be physical or software devices accessible through a touch screen. Buttons, switches or dials may be physically connected to the housing 4010 in one form or may be in wireless communication with a receiver electrically connected to the central controller 4230 in another form.

In one form, the input device 4220 may be constructed and arranged to allow a person to select values and/or menu options.

5.4.2.3 Central controller

In one form of the present technology, the central controller 4230 is one or more processors adapted to control the RPT device 4000.

Suitable processors may include x86 INTEL processors,based on ARM Holdings

A processor of an M-processor, such as the STM32 family microcontroller of ST MICROELECTRONIC. In certain alternatives of the present technique, a 32-bit RIS CCPU (such as the STR9 series microcontroller from ST MICROELECTRONICS) or a 16-bit RISC CPU (such as the processor of the MSP430 series microcontroller manufactured by TEXAS INSTRUMENTS) may also be suitable.

In one form of the present technology, the central controller 4230 is a dedicated electronic circuit.

In one form, central controller 4230 is an application specific integrated circuit. In another form, the central controller 4230 comprises discrete electronic components.

The central controller 4230 may be configured to receive input signals from the one or more transducers 4270, the one or more input devices 4220, and the humidifier 5000.

The central controller 4230 may be configured to provide output signals to one or more of the output device 4290, the therapy device controller 4240, the data communication interface 4280, and the humidifier 5000.

In some forms of the present technology, the central controller 4230 is configured to implement one or more methods described herein, such as one or more algorithms 4300 represented as a computer program stored in a non-transitory computer-readable storage medium (e.g., memory 4260). In some forms of the present technology, the central controller 4230 may be integrated with the RPT device 4000. However, in some forms of the present technology, some methods may be performed by a remotely located device. For example, a remotely located device may determine control settings of a ventilator or detect respiratory-related events by analyzing stored data (e.g., from any of the sensors described herein).

5.4.2.4 clock

The RPT device 4000 may comprise a clock 4232 connected to a central controller 4230.

5.4.2.5 therapeutic equipment controller

In one form of the present technology, the treatment device controller 4240 is a treatment control module 4330, which forms part of an algorithm 4300 executed by the central controller 4230.

In one form of the present technology, the treatment device controller 4240 is a dedicated motor control integrated circuit. For example, in one form, a MC33035 brushless DC motor controller manufactured by ONSEMI is used.

5.4.2.6 protection circuit

The one or more protection circuits 4250 in accordance with the present technology may include electrical protection circuits, temperature and/or pressure safety circuits.

5.4.2.7 memory

In accordance with one form of the present technique, the RPT device 4000 includes a memory 4260, such as a non-volatile memory. In some forms, memory 4260 may comprise battery-powered static RAM. In some forms, the memory 4260 may comprise volatile RAM.

Memory 4260 may be located on PCBA 4202. The memory 4260 may be in the form of EEPROM or NAND flash memory.

Additionally or alternatively, the RPT device 4000 includes a memory 4260 in a removable form, such as a memory card manufactured according to the Secure Digital (SD) standard.

In one form of the present technology, the memory 4260 serves as a non-transitory computer-readable storage medium having stored thereon computer program instructions representing one or more methods described herein, such as one or more algorithms 4300.

5.4.2.8 data communication system

In one form of the present technology, a data communication interface 4280 is provided which is connected to the central controller 4230. Data communication interface 4280 may connect to remote external communication network 4282 and/or local external communication network 4284. The remote external communication network 4282 may be connected to a remote external device 4286. The local external communication network 4284 may be connected to a local external device 4288.

In one form, the data communication interface 4280 is part of the central controller 4230. In another form, the data communication interface 4280 is separate from the central controller 4230 and may comprise an integrated circuit or processor.

In one form, the remote external communication network 4282 is the internet. Data communication interface 4280 may connect to the internet using wired communication (e.g., via ethernet or fiber optics) or wireless protocols (e.g., CDMA, GSM, LTE).

In one form, the local external communication network 4284 utilizes one or more communication standards, such as bluetooth or a consumer infrared protocol.

In one form, the remote external device 4286 is one or more computers, such as a cluster of networked computers. In one form, the remote external device 4286 may be a virtual computer, rather than a physical computer. In either case, such a remote external device 4286 may be accessed by an appropriately authorized person, such as a clinician.

The local external device 4288 may be a personal computer, mobile phone, tablet, or remote control device.

5.4.2.9 includes optional display, alarm output device

Output devices 4290 in accordance with the present technology may take the form of one or more of visual, audio, and haptic units. The visual display may be a Liquid Crystal Display (LCD) or a Light Emitting Diode (LED) display.

5.4.2.9.1 display driver

The display driver 4292 receives as input characters, symbols, or images to be displayed on the display 4294, and converts them into commands for causing the display 4294 to display the characters, symbols, or images.

5.4.2.9.2 display

The display 4294 is configured to visually display characters, symbols, or images in response to commands received from the display driver 4292. For example, the display 4294 may be an eight-segment display, in which case the display driver 4292 converts each character or symbol (e.g., fig. 0) into 8 logic signals indicating whether 8 respective segments are to be activated to display the particular character or symbol.

5.4.3RPT device Algorithm

As described above, in some forms of the present technology, the central controller 4230 may be configured to implement one or more algorithms 4300 represented as a computer program stored in a non-transitory computer-readable storage medium (e.g., memory 4260). The algorithm 4300 is generally grouped into groups called modules.

In other forms of the present technology, some portion or all of the algorithm 4300 may be implemented by a controller of an external device, such as the local external device 4288 or the remote external device 4286. In this form, data representing input signals and/or intermediate algorithm outputs required to perform portions of the algorithm 4300 at an external device may be transmitted to the external device via the local external communication network 4284 or the remote external communication network 4282. In this form, the portion of the algorithm 4300 to be executed at the external device may be represented as a computer program stored in a non-transitory computer readable storage medium accessible to a controller of the external device. Such a program configures the controller of the external device to perform portions of the algorithm 4300.

In such a form, the therapy parameters generated by the external device via the therapy engine module 4320 (if so forming part of the algorithm 4300 executed by the external device) may be communicated to the central controller 4230 to be communicated to the therapy control module 4330.

5.4.3.1 preprocessing module

A pre-processing module 4310 according to one form of the present technology receives as input a signal from a transducer 4270 (e.g., a flow sensor 4274 or a pressure sensor 4272) and performs one or more processing steps to calculate one or more output values to be used as input to another module (e.g., a therapy engine module 4320).

In one form of the present technique, the output values include the interface pressure Pm, the respiratory flow Qr, and the leakage flow Ql.

In various forms of the present technology, the pre-processing module 4310 includes one or more of the following algorithms: interface pressure estimate 4312, ventilation flow estimate 4314, leakage flow estimate 4316, and respiratory flow estimate 4318.

5.4.3.1.1 interface pressure estimation

In one form of the present technique, the interfacial pressure estimation algorithm 4312 receives as inputs a signal from a pressure sensor 4272 indicative of the pressure in the pneumatic path adjacent the outlet of the pneumatic block (device pressure Pd) and a signal from a flow sensor 4274 representative of the flow rate of the gas stream exiting the RPT device 4000 (device flow rate Qd). In the absence of any make-up gas 4180, the device flow rate Qd may be used as the total flow rate Qt. The interface pressure algorithm 4312 estimates the pressure drop Δ P across the air circuit 4170. The dependence of the pressure drop Δ P on the total flow Qt may be modeled for a particular air circuit 4170 by a pressure drop characteristic Δ P (q). The interface pressure estimation algorithm 4312 then provides the estimated pressure Pm as an output in the patient interface 3000 or 3800. The pressure Pm in the patient interface 3000 or 3800 may be estimated as the device pressure Pd minus the air circuit pressure drop Δ P.

5.4.3.1.2 ventilation flow estimation

In one form of the present technology, the ventilation flow estimation algorithm 4314 receives as input the estimated pressure Pm in the patient interface 3000 or 3800 from the interface pressure estimation algorithm 4312 and estimates the ventilation flow Qv of air from the vent 3400 in the patient interface 3000 or 3800. For a particular vent 3400 in use, the dependence of the vent flow Qv on the vent pressure Pm can be modeled by the vent characteristics Qv (Pm).

5.4.3.1.3 leakage flow estimation

In one form of the present technique, the leakage flow estimation algorithm 4316 receives as inputs the total flow Qt and the vent flow Qv, and provides as an output an estimate of the leakage flow Ql. In one form, the leak flow estimation algorithm estimates the leak flow Ql by averaging the difference between the total flow Qt and the ventilation flow Qv over a sufficiently long period of time (e.g., about 10 seconds).

In one form, leak flow estimation algorithm 4316 receives total flow Qt, ventilation flow Qv, and estimated pressure Pm as inputs in patient interface 3000 or 3800 and provides leak flow Ql as an output by calculating leak conductance and determining leak flow Ql as a function of leak conductance and pressure Pm. The leak conductance is calculated as the quotient of a low-pass filtered non-ventilation flow equal to the difference between total flow Qt and ventilation flow Qv, and the square root of pressure Pm, where the low-pass filter time constant has a value long enough to encompass several breathing cycles, for example about 10 seconds. The leakage flow Ql may be estimated as the product of the leakage conductance and a function of the pressure Pm.

5.4.3.1.4 respiratory flow estimation

In one form of the present technique, respiratory flow estimation algorithm 4318 receives total flow Qt, ventilation flow Qv, and leakage flow Ql as inputs and estimates respiratory flow Qr of air to the patient by subtracting ventilation flow Qv and leakage flow Ql from total flow Qt.

5.4.3.2 therapy engine module

In one form of the present technology, the therapy engine module 4320 receives as inputs one or more of the pressure Pm in the patient interface 3000 or 3800 and the respiratory flow of air Qr to the patient and provides as outputs one or more therapy parameters.

In one form of the present technique, the treatment parameter is a treatment pressure Pt.

In one form of the present technology, the treatment parameter is one or more of a pressure variation amplitude, a base pressure, and a target ventilation.

In various forms, the therapy engine module 4320 includes one or more of the following algorithms: phase determination 4321, waveform determination 4322, ventilation determination 4323, inspiratory flow limitation determination 4324, apnea/hypopnea determination 4325, snoring determination 4326, airway patency determination 4327, target ventilation determination 4328, and therapy parameter determination 4329.

5.4.3.2.1 phase determination

In one form of the present technique, the RPT device 4000 does not determine phase.

In one form of the present technique, the phase determination algorithm 4321 receives as input a signal indicative of the respiratory flow Qr and provides as output the phase Φ of the current respiratory cycle of the patient 1000.

In some forms, referred to as discrete phase determination, the phase output Φ is a discrete variable. One implementation of discrete phase determination provides a two-valued phase output Φ with an inspiration or expiration value, e.g., values represented as 0 and 0.5 revolutions, respectively, upon detection of the onset of spontaneous inspiration and expiration, respectively. The "triggered" and "cycled" RPT devices 4000 effectively perform discrete phase determination, since the trigger point and the cycle point are the time instants at which the phase changes from expiration to inspiration and from inspiration to expiration, respectively. In one implementation of the two-value phase determination, the phase output Φ is determined to have a discrete value of 0 (thereby "triggering" the RPT device 4000) when the respiratory flow Qr has a value that exceeds a positive threshold, and is determined to have a discrete value of 0.5 revolutions (thereby "cycling" the RPT device 4000) when the respiratory flow Qr has a value that is more negative than a negative threshold. Inspiration time Ti and expiration time Te may be estimated as typical values over a number of respiratory cycles for the time it takes for phase Φ to equal 0 (representing inspiration) and 0.5 (representing expiration), respectively.

Another implementation of discrete phase determination provides a three-value phase output Φ having a value of one of inspiration, intermediate inspiration pause, and expiration.

In other forms, known as continuous phase determination, the phase output Φ is a continuous variable, e.g., going from 0 to 1 revolution, or 0 to 2 π radians. The RPT device 4000 performing continuous phase determination may trigger and cycle when the continuous phase reaches 0 and 0.5 revolutions, respectively. In one implementation of continuous phase determination, a fuzzy logic analysis of respiratory flow Qr is used to determine a continuous value of phase Φ. The continuous value of the phase determined in this implementation is commonly referred to as the "blurred phase". In one implementation of the fuzzy phase determination algorithm 4321, the following rule is applied to the respiratory flow Qr:

1. if the respiratory flow is zero and increases rapidly, the phase is 0 revolutions.

2. If the respiratory flow is large, positive and stable, the phase is 0.25 revolutions.

3. If the respiratory flow is zero and drops rapidly, the phase is 0.5 revolutions.

4. If the respiratory flow is large, negative and stable, the phase is 0.75 revolutions.

5. If the respiratory flow is zero and stable and the 5 second low pass filtered absolute value of the respiratory flow is large, the phase is 0.9 revolutions.

6. If the respiratory flow is positive and the phase is expiratory, the phase is 0 revolutions.

7. If the respiratory flow is negative and the phase is inspiration, the phase is 0.5 revolutions.

8. If the 5 second low pass filtered absolute value of respiratory flow is large, the phase is increased at a steady rate equal to the patient's respiratory rate, low pass filtered with a time constant of 20 seconds.

The output of each rule can be represented as a vector whose phase is the result of the rule and whose magnitude is the degree of ambiguity that the rule is true. The degree of ambiguity in respiratory flow "large", "steady", etc. is determined by appropriate membership functions. The results of the rules are represented as vectors, which are then combined by some function, such as coring. In such a combination, the rules may be weighted equally, weighted differently.

In another implementation of continuous phase determination, the phase Φ is first estimated discretely from the respiratory flow Qr as described above, as are the inhale time Ti and exhale time Te. The continuous phase Φ at any instant can be determined as a proportion of half the inspiratory time Ti that has elapsed since the previous trigger instant, or 0.5 revolutions plus half the expiratory time Te that has elapsed since the previous cycle instant (whichever is closer).

5.4.3.2.2 waveform determination

In one form of the present technique, the therapy parameter determination algorithm 4329 provides an approximately constant therapy pressure throughout the patient's respiratory cycle.

In other forms of the present technique, the therapy control module 4330 controls the pressure generator 4140 to provide a therapy pressure Pt that varies as a function of the phase Φ of the patient's respiratory cycle according to the waveform template Π (Φ).

In one form of the present technique, the waveform determination algorithm 4322 provides a waveform template Π (Φ) of values in the range of [0, 1] over the domain of phase values Φ provided by the phase determination algorithm 4321 for use by the treatment parameter determination algorithm 4329.

In one form suitable for discrete or continuous value phases, the waveform template Π (Φ) is a square wave template having a value of 1 for phase values up to and including 0.5 revolutions and a value of 0 for phase values greater than 0.5 revolutions. In one form suitable for continuous value phases, the waveform template Π (Φ) includes two smoothly curved portions, i.e., a smoothly curved (e.g., raised cosine) rising from 0 to 1 for phase values up to 0.5 revolutions, and a smoothly curved (e.g., exponential) decaying from 1 to 0 for phase values greater than 0.5 revolutions. In one form suitable for continuous value phases, the waveform template Π (Φ) is based on a square wave, but rises smoothly from 0 to 1 for phase values up to a "rise time" of less than 0.5 revolution, and falls smoothly from 1 to 0 for phase values within a "fall time" after 0.5 revolution, where the "fall time" is less than 0.5 revolution.

In some forms of the present technique, the waveform determination algorithm 4322 selects a waveform template Π (Φ) from the waveform template library according to the settings of the RPT device. Each waveform template Π (Φ) in the library may be provided as a look-up table of values Π relative to phase values Φ. In other forms, the waveform determination algorithm 4322 calculates the waveform template Π (Φ) "on the fly" using a predetermined functional form, which may be parameterized by one or more parameters (e.g., the time constant of an exponential curve portion). The parameters of the functional form may be predetermined or dependent on the current state of the patient 1000.

In some forms of the present technology, a discrete binary phase appropriate for inhalation (Φ 0 revolutions) or exhalation (Φ 0.5 revolutions), the waveform determination algorithm 4322 calculates the waveform template Π "on the fly" from the discrete phase Φ and the time t measured from the most recent trigger time. In one such form, the waveform determination algorithm 4322 calculates the waveform template Π (Φ, t) in both portions (inspiration and expiration) as follows:

II therein_i(t) and Π_e(t) is the inspiratory and expiratory portion of waveform template Π (Φ, t). In one such form, the suction portion Π of the corrugated form is_i(t) is parameterized by rise time from 0 to1, smoothly rises, and the expiration part pi of the waveform template_e(t) is a smooth drop from 1 to 0 parameterized by the drop time.

5.4.3.2.3 Ventilation determination

In one form of the present technique, the ventilation determination algorithm 4323 receives an input of the respiratory flow Qr and determines a measurement indicative of the current patient ventilation Vent.

In some implementations, the ventilation determination algorithm 4323 determines a measure of ventilation Vent as an estimate of actual patient ventilation. One such implementation is to take half the absolute value of the respiratory flow Qr, optionally filtered by a low pass filter such as a second order bessel low pass filter with a corner frequency of 0.11 Hz.

In other implementations, the ventilation determination algorithm 4323 determines a measure of ventilation Vent that is approximately proportional to the actual patient ventilation. One such implementation estimates the peak respiratory flow Qpeak over the inspiratory portion of the cycle. This process, and many other processes involving sampling of the respiratory flow Qr, produces a measurement that is approximately proportional to ventilation, as long as the flow waveform shape does not vary greatly (here, when the flow waveforms of breaths normalized in time and amplitude are similar, the shapes of the two breaths are considered similar). Some simple examples include the median of positive respiratory flow, the median of absolute values of respiratory flow, and the standard deviation of flow. Any linear combination of any order of magnitude of the absolute value of respiratory flow using positive coefficients, and even some using positive and negative coefficients, is approximately proportional to ventilation. Another example is the average of respiratory flow in the middle K proportion (in time) of the inspiratory portion, where 0< K < 1. If the flow shape is constant, there are any number of measurements that are precisely proportional to ventilation.

5.4.3.2.4 determination of inspiratory flow limitation

In one form of the present technique, central controller 4230 executes an inspiratory flow limitation determination algorithm 4324 for determining the degree of inspiratory flow limitation.

In one form, inspiratory flow limitation determination algorithm 4324 receives as input the respiratory flow signal Qr and provides as output a measure of the extent to which the inspiratory portion of the breath exhibits inspiratory flow limitation.

In one form of the present technique, the inspiratory portion of each breath is identified by a zero-crossing detector. A plurality of evenly spaced points (e.g., 65) representing time points are interpolated by an interpolator along the inspiratory flow-time curve for each breath. The curve described by the points is then scaled by a scalar to have a uniform length (duration/period) and uniform area to eliminate the effect of varying respiration rate and depth. The scaled breath is then compared in a comparator to a pre-stored template representing normal, unobstructed breath, similar to the inspiratory portion of breath shown in fig. 6A. At any time during inspiration from the template, breaths deviating beyond a specified threshold (typically 1 scale unit) are rejected, such as those breaths due to coughing, sighing, swallowing, and hiccups as determined by the test element. For non-rejected data, a moving average of the first such scaling points of the previous several inhalation events is calculated by the central controller 4230. For the second such point, this repeats over the same inspiratory event, and so on. Thus, for example, 65 scaled data points are generated by the central controller 4230 and represent a moving average of the previous several inspiratory events (e.g., three events). The moving average of the continuously updated values of (e.g., sixty-five) points is hereinafter referred to as "scaled flow rate" and is denoted as qs (t). Alternatively, a single inspiratory event may be used rather than a moving average.

From the scaled flow, two form factors can be calculated that are relevant for determining partial obstruction.

The shape factor 1 is the ratio of the average of the intermediate (e.g., 32) scaled flow points to the total average (e.g., 65) scaled flow points. When this ratio exceeds 1, breathing will be normal. When the ratio is 1 or less, breathing will be blocked. A ratio of about 1.17 is taken as a threshold between partially occluded and non-occluded breaths and is equal to the degree of occlusion that allows sufficient oxygenation to be maintained in a typical patient.

The form factor 2 is calculated as the RMS deviation of the unit scaled flow at the middle (e.g., 32) points. An RMS deviation of about 0.2 units is considered normal. A zero RMS deviation is considered to be a full flow limited breath. The closer the RMS deviation is to zero, the more flow limited the breath will be considered.

Form factors 1 and 2 may be used as an alternative, or in combination. In other forms of the present technique, the number of sampling points, breaths, and intermediate points may be different from those described above. Furthermore, the threshold may be different from the described threshold.

5.4.3.2.5 determination of apnea and hypopnea

In one form of the present technology, the central controller 4230 executes an apnea/hypopnea determination algorithm 4325 for determining the presence of apnea and/or hypopnea.

In one form, the apnea/hypopnea determination algorithm 4325 receives the respiratory flow signal Qr as an input and provides as an output a flag indicating that an apnea or hypopnea has been detected.

In one form, an apnea will be considered to have been detected when a function of the respiratory flow Qr falls below a flow threshold for a predetermined period of time. The function may determine peak flow, a relatively short term average flow, or an intermediate flow of the relatively short term average and peak flows, such as RMS flow. The flow threshold may be a relatively long-term measure of flow.

In one form, a hypopnea will be deemed to have been detected when a function of the respiratory flow Qr falls below a second flow threshold within a predetermined period of time. The function may determine peak flow, average flow over a relatively short period, or intermediate flow between average and peak flow over a relatively short period, such as RMS flow. The second flow threshold may be a relatively long term flow measurement. The second flow threshold is greater than the flow threshold for detecting apneas.

5.4.3.2.6 determination of snoring

In one form of the present technology, the central controller 4230 executes one or more snore determining algorithms 4326 for determining the degree of snoring.

In one form, snore determining algorithm 4326 receives respiratory flow signal Qr as an input and provides as an output a measure of the extent to which snoring is occurring.

Snore determining algorithm 4326 can include a step of determining the intensity of the flow signal in the range of 30-300 Hz. Further, snore determining algorithm 4326 can include a step of filtering the respiratory flow signal Qr to reduce background noise (e.g., sounds from airflow in a system of a blower).

5.4.3.2.7 determination of airway patency

In one form of the present technology, the central controller 4230 executes one or more airway patency determination algorithms 4327 for determining the degree of airway patency.

In one form, airway patency determination algorithm 4327 receives respiratory flow signal Qr as an input and determines the power of the signal in a frequency range of about 0.75Hz and about 3 Hz. The presence of a peak in this frequency range indicates airway patency. The absence of a peak is considered an indication of a closed airway.

In one form, the frequency range in which the peak is sought is the frequency of a small forced oscillation in the treatment pressure Pt. In one implementation, the forced oscillation has a frequency of 2Hz and an amplitude of about 1cmH₂O。

In one form, the airway patency determination algorithm 4327 receives the respiratory flow signal Qr as an input and determines whether a cardiogenic signal is present. The absence of cardiogenic signals is considered to be an indication of closed airways.

5.4.3.2.8 determination of target ventilation

In one form of the present technique, the central controller 4230 takes as input a measurement of the current ventilation Vent and executes one or more target ventilation determination algorithms 4328 for determining a target value Vtgt for the ventilation measurement.

In some forms of the present technique, the target ventilation determination algorithm 4328 is absent, and the target Vtgt is predetermined, for example, by hard coding during configuration of the RPT device 4000 or by manual input through the input device 4220.

In other forms of the present technique, such as Adaptive Servo Ventilation (ASV), the target ventilation determination algorithm 4328 calculates the target Vtgt from a value Vtyp indicative of the typical recent ventilation of the patient.

In some forms of adaptive servo ventilation, the target ventilation Vtgt is calculated as a high proportion of the typical recent ventilation Vtyp, but less than the typical recent ventilation Vtyp. The high proportion of this form may be in the range (80%, 100%) or (85%, 95%) or (87%, 92%).

In other forms of adaptive servo ventilation, the target ventilation Vtgt is calculated to be slightly greater than an integer multiple of the typical recent ventilation Vtyp.

A typical recent ventilation Vtyp is a value around which the distribution of the measured values of the current ventilation Vent at a number of times over some predetermined time scale gathers, i.e. a measure of the central tendency of the measurement of the current ventilation over the recent history. In one implementation of the target ventilation determination algorithm 4328, the recent history is on the order of a few minutes, but in any event should be longer than the time scale of the tidal rich-lean period. The target ventilation determination algorithm 4328 may use any of a variety of well-known measures of central tendency to determine a typical recent ventilation Vtyp from a measure of the current ventilation Vent. One such measure is the output of the low pass filter on the measure of the current ventilation Vent, with a time constant equal to one hundred seconds.

5.4.3.2.9 determination of treatment parameters

In some forms of the present technology, the central controller 4230 executes one or more therapy parameter determination algorithms 4329 for determining one or more therapy parameters using values returned by one or more other algorithms in the therapy engine module 4320.

In one form of the present technique, the treatment parameter is the instantaneous treatment pressure Pt. In one implementation of this form, the treatment parameter determination algorithm 4329 uses an equation to determine the treatment pressure Pt

Pt＝AΠ(Φ,t)+P₀ (1)

Wherein:

a is the amplitude of the vibration,

Π (Φ, t) is the waveform template value at the current value Φ of phase and time t (in the range 0 to 1), and

·P₀is the base pressure.

If the waveform determination algorithm 4322 provides the waveform template Π (Φ, t) as a lookup table of values Π indexed by phase Φ, the treatment parameter determination algorithm 4329 applies equation (1) by locating the lookup table entry closest to the current value Φ of the phase returned by the phase determination algorithm 4321, or by interpolating between the two entries across the current value Φ of the phase.

Amplitude A and base pressure P₀May be set by the therapy parameter determination algorithm 4329 in the following manner depending on the selected respiratory pressure therapy mode.

5.4.3.3 therapy control Module

The therapy control module 4330, according to one aspect of the present technology, receives as input therapy parameters from the therapy parameter determination algorithm 4329 of the therapy engine module 4320 and controls the pressure generator 4140 to deliver the airflow according to the therapy parameters.

In one form of the present technology, the therapy parameter is therapy pressure Pt, and therapy control module 4330 controls pressure generator 4140 to deliver an air flow at patient interface 3000 or 3800 with interface pressure Pm equal to therapy pressure Pt.

5.4.3.4 detection of a fault condition

In one form of the present technology, the central controller 4230 executes one or more methods 4340 for detecting fault conditions. The fault condition detected by one or more methods 4340 may include at least one of:

power failure (without power supply or power supply failure)

Converter failure detection

Failure to detect the presence of a component

Operating parameters outside of recommended ranges (e.g. pressure, flow rate, temperature, PaO)₂)

Failure of the test alarm to produce a detectable alarm signal.

Upon detection of a fault condition, the corresponding algorithm 4340 signals the presence of a fault by one or more of:

initiating an audible, visual and/or dynamic (e.g. vibratory) alarm

Sending a message to an external device

Event logging

5.5 air Circuit

The air circuit 4170 in accordance with one aspect of the present technique is a conduit or tube that, in use, is constructed and arranged to allow a flow of air to travel between two components, such as the RPT device 4000 and the patient interface 3000 or 3800.

Specifically, the air circuit 4170 may be fluidly connected with the outlet of the pneumatic block 4020 and the patient interface. The air circuit may be referred to as an air delivery tube. In some cases, there may be separate branches for the inhalation and exhalation circuits. In other cases, a single branch is used.

In some forms, the air circuit 4170 may include one or more heating elements configured to heat the air in the air circuit, e.g., to maintain or raise the temperature of the air. The heating element may be in the form of a heating wire loop and may comprise one or more transducers, such as temperature sensors. In one form, the heating wire loop may be helically wound about the axis of the air loop 4170. The heating element may be in communication with a controller, such as central controller 4230. One example of an air circuit 4170 including a heated wire circuit is described in U.S. patent No. 8,733,349, which is incorporated herein by reference in its entirety.

5.5.1 make-up gas delivery

In one form of the present technique, a supplemental gas (e.g. oxygen) 4180 is delivered to one or more points in the pneumatic path, e.g. upstream of pneumatic block 4020, to air circuit 4170 and/or patient interface 3000.

5.6 humidifier

5.6.1 humidifier overview

In one form of the present technology, a humidifier 5000 (e.g., as shown in fig. 5A) is provided to vary the absolute humidity of the air or gas for delivery to the patient relative to the ambient air. Generally, the humidifier 5000 is used to increase the absolute humidity of the air flow and increase the temperature of the air flow (relative to ambient air) prior to delivery to the patient's airway.

The humidifier 5000 may include a humidifier reservoir 5110, a humidifier inlet 5002 for receiving the air flow, and a humidifier outlet 5004 for delivering the humidified air flow. In some forms, as shown in fig. 5A and 5B, the inlet and outlet of the humidifier reservoir 5110 may be the humidifier inlet 5002 and humidifier outlet 5004, respectively. The humidifier 5000 may also include a humidifier base 5006, which may be adapted to receive a humidifier reservoir 5110 and include a heating element 5240.

5.6.2 humidifier Components

5.6.2.1 Water storage device

According to one arrangement, the humidifier 5000 may include a water reservoir 5110 configured to hold or retain a volume of liquid (e.g., water) to be evaporated for humidifying the air flow. The water reservoir 5110 may be configured to maintain a predetermined maximum water volume so as to provide sufficient humidification for at least the duration of a respiratory therapy session, such as one night of sleep. Typically, the reservoir 5110 is configured to hold several hundred milliliters of water, e.g., 300 milliliters (ml), 325ml, 350ml, or 400 ml. In other forms, the humidifier 5000 may be configured to receive a supply of water from an external water source, such as a building's water supply.

According to one aspect, the water reservoir 5110 is configured to add humidity to the air flow from the RPT device 4000 as the air flow travels therethrough. In one form, the water reservoir 5110 may be configured to promote airflow traveling in a tortuous path through the reservoir 5110 while in contact with a volume of water therein.

According to one form, the reservoir 5110 may be removed from the humidifier 5000, for example, in a lateral direction as shown in fig. 5A and 5B.

The reservoir 5110 may also be configured to prevent liquid from flowing out of it, such as through any of the apertures and/or in the middle of its subcomponents, such as when the reservoir 5110 is displaced and/or rotated from its normal operating orientation. Since the air flow to be humidified by the humidifier 5000 is typically pressurized, the reservoir 5110 may also be configured to avoid loss of pneumatic pressure through leakage and/or flow impedance.

5.6.2.2 conductive part

According to one arrangement, the reservoir 5110 includes a conductive portion 5120 configured to allow efficient transfer of heat from the heating element 5240 to the liquid volume in the reservoir 5110. In one form, conductive portion 5120 can be arranged as a plate, although other shapes can be equally suitable. All or a portion of the conductive portion 5120 can be made of a thermally conductive material, such as aluminum (e.g., about 2mm thick, such as 1mm, 1.5mm, 2.5mm, or 3mm), another thermally conductive metal, or some plastic. In some cases, suitable thermal conductivity may be achieved with materials of suitable geometry that are less conductive.

5.6.2.3 humidifier storage base

In one form, the humidifier 5000 can include a humidifier reservoir base 5130 (shown in fig. 5B) configured to receive the humidifier reservoir 5110. In some arrangements, the humidifier reservoir base 5130 may include a locking feature, such as a locking lever 5135 configured to retain the reservoir 5110 in the humidifier reservoir base 5130.

5.6.2.4 Water level indicator

The humidifier reservoir 5110 may include a water level indicator 5150 as shown in fig. 5A-5B. In some forms, the water level indicator 5150 may provide a user (such as a patient 1000 or caregiver) with one or more indications as to the amount of water volume in the humidifier reservoir 5110. The one or more indications provided by the water level indicator 5150 may include an indication of a maximum predetermined volume of water, any portion thereof, such as 25%, 50%, 75%, or a volume such as 200ml, 300ml, or 400 ml.

5.6.2.5 humidifier converter

The humidifier 5000 may include one or more humidifier transducers (sensors) 5210 instead of or in addition to the transducer 4270 described above. As shown in fig. 5C, the humidifier converter 5210 may include one or more of an air pressure sensor 5212, an air flow converter 5214, a temperature sensor 5216, or a humidity sensor 5218. The humidifier converter 5210 may generate one or more output signals that may be in communication with a controller, such as the central controller 4230 and/or the humidifier controller 5250. In some forms, the humidifier converter may be located external to the humidifier 5000 (such as in the air circuit 4170) when communicating the output signal to the controller.

5.6.2.5.1 pressure transducer

One or more pressure transducers 5212 may be provided to the humidifier 5000 in addition to, or in place of, the pressure sensors 4272 provided in the RPT device 4000.

5.6.2.5.2 air flow converter

One or more flow transducers 5214 may be provided to the humidifier 5000 in addition to, or in place of, the flow sensor 4274 provided in the RPT device 4000.

5.6.2.5.3 temperature converter

The humidifier 5000 may include one or more temperature converters 5216. The one or more temperature transducers 5216 can be configured to measure one or more temperatures of the air flow downstream of the heating element 5240 and/or the humidifier outlet 5004, for example. In some forms, the humidifier 5000 may also include a temperature sensor 5216 to detect the temperature of the ambient air.

5.6.2.5.4 humidity transducer

In one form, the humidifier 5000 may include one or more humidity sensors 5218 to detect the humidity of the gas (e.g., ambient air). A humidity sensor 5218 may be provided in some form towards the humidifier outlet 5004 to measure the humidity of the gases delivered from the humidifier 5000. The humidity sensor may be an absolute humidity sensor or a relative humidity sensor.

5.6.2.6 heating element

In some cases, a heating element 5240 may be provided to the humidifier 5000 to provide a heat input to one or more volumes of water and/or air flow in the humidifier reservoir 5110. The heating element 5240 may comprise a heat generating component, such as a resistive heating track. One suitable example of a heating element 5240 is a layered heating element, such as in PCT patent application publication No. WO2012/171072, which is incorporated by reference herein in its entirety.

In some forms, the heating element 5240 can be disposed in the humidifier base 5006, where heat can be provided primarily by conduction to the humidifier reservoir 5110, as shown in fig. 5B.

5.6.2.7 humidifier controller

In accordance with arrangements of the present technology, the humidifier 5000 may include a humidifier controller 5250 as shown in fig. 5C. In one form, the humidifier controller 5250 may be part of the central controller 4230. In another form, the humidifier controller 5250 may be a separate controller, which may be in communication with the central controller 4230.

In one form, the humidifier controller 5250 may receive as input measurements of characteristics of the flow of air, water (such as temperature, humidity, pressure and/or flow), for example, in the reservoir 5110 and/or the humidifier 5000. The humidifier controller 5250 may also be configured to perform or implement a humidifier algorithm and/or deliver one or more output signals.

As shown in fig. 5C, the humidifier controller 5250 may include one or more controllers, such as a central humidifier controller 5251, a heated air circuit controller 5254 configured to control the temperature of the heated air circuit 4171, and/or a heating element controller 5252 configured to control the temperature of the heating element 5240.

5.7 tube type identification

In one form of the present technology, a system and/or method is provided for identifying the type of peripheral component (e.g., the type of air delivery tube 4170 and/or patient interface) connected to the RPT device 4000. In some examples, the air delivery tube type may be determined based on one or more unique electrical characteristics of the air delivery tube 4170 and/or one or more unique connectors of the air delivery tube 4170. In one example, the contact assembly coupling the air delivery tube 4170 to the air delivery tube 4170 of the RPT device 4000 may be used as an identifier of various parameters of the air delivery tube 4170 and/or the patient interface. For example, the contact assembly may be configured to provide identification of the type of air delivery tube 4170 (e.g., non-heated tube, tube with Heat Moisture Exchanger (HME), unknown tube), the dimensions of the air delivery tube (e.g., 15mm, 19mm), the presence and type of HME, the type of patient interface connected to the tube, and so forth. Data from the identification may be communicated and used by the controller to optimize the operation of the RPT device 4000 and/or the humidifier 5000. For example, the controller may be configured to identify unique identifying features such that the controller may identify particular features of the air delivery tube 4170 coupled to the RPT device 4000, and thus the controller may automatically configure the RPT device 4000 and/or the humidifier 5000 to optimize operation.

Fig. 5D-5H show schematic views of air delivery tube 4170 connected to RPT device 4000 in accordance with various forms of the present technique. Each schematic illustrates that the air delivery tube 4170 may provide different features that may be used to identify the type of tube connected to the RPT device 4000.

The RPT device 4000 may include a contact assembly 6200 for mechanically and electrically coupling to the tube connector 6300 to provide power, signals, and/or air to the air delivery tube 4170. The contact assembly 6200 may be provided as a separate component coupled to or integrated into the housing of the RPT device 4000 or humidifier 5000. The connections in the tube may be solid pins, but are not so limited. In some examples, the connections may be provided by, for example, lead frame terminals. In one example, when the tube 4170 is connected, the solid pins in one of the devices connect to the corresponding pogo pins in the other device.

In one form of the present disclosure, the contact assembly 6200 includes four connections coupled to the processing circuitry 6400. The processing circuitry 6400 may be provided as part of the central controller 4230, the central humidifier controller 5251, the air circuit controller 5254, or as separate circuits coupled to the central controller 4230, the central humidifier controller 5251, and/or the air circuit controller 5254. The processing circuit 6400 may include one or more analog and/or digital hardware elements for performing the operations discussed in this application.

In one form of the present disclosure, at least two connections (heater wire 1 and heater wire 2) are coupled to the heating control circuit, and two connections (sensor wire 1 and sensor wire 2) are coupled to the cartridge detection circuit. One heater wire may be coupled to the ground of the heating control circuit. In some examples, one or both of the sensor wire connections may be coupled to a sensor 6500 having an electrical characteristic (e.g., resistance) that is dependent on temperature. Sensor 6500 may comprise a thermistor formed from a Negative Temperature Coefficient (NTC) material. The parameters of the thermistor (e.g., resistance) may vary as the tube temperature changes.

The heater control circuit may provide power to the heating element in the tube 4170 via a switch (e.g., a transistor). The heating element may comprise heating wires distributed to the mask end of tube 4170 along at least a portion of the length of tube 4170. The heater control circuit may control the duration, voltage, and/or frequency and/or period of a Pulse Width Modulation (PWM) signal provided to the heating element 5240 in the tube 4170.

The heat pipe detection circuit may be configured to receive a signal from the sensor 6500 disposed in the pipe 4170 indicative of operation of the heating element in the pipe 4170. Sensor 6500 may be disposed at the mask proximal end of tube 4170. For example, the heat pipe detection circuit may measure the voltage and/or current of the sensor 6500 to determine an operating characteristic (e.g., temperature) of the heating element. The heater control circuit may control the heating element based on the signal received by the heat pipe detection circuit and the setting of the heat pipe 4170. Other sensors, i.e. humidity sensors, arranged anywhere in the tube may also be connected in a similar manner.

The heater tube detection circuit may automatically identify the type of tube 4170 connected to the RPT device 4000 based on the unique characteristic(s) provided by the active and/or passive components in the tube 4170 or the absence of any connecting components via one or more of the four electrical connectors between the tube 4170 and the RPT device 4000. Based on the indicated type of tube 4170 connected, the controller may change the operating parameters of the system. For example, different heating control settings may be provided for different tubes (e.g., non-heated tubes, tubes with Heat Moisture Exchangers (HMEs), unknown tubes). In some examples, the settings may be modified based on the identified size of the air delivery tube (e.g., 15mm, 19mm), the presence and type of HME, the type of patient interface connected to the tube, and so forth.

5.7.1 four-foot four-wire tag

In fig. 5D, the heating element is coupled to two pins in the tube 4170 and the sensor 6500 is coupled to two other pins in the tube 4170. The characteristics of the sensor 6500 and/or heating element may be used to identify the type of pipe connected to the RPT device 4000. For example, the thermistor may be selected based on the type of the air delivery tube 4170. A 10k thermistor may be provided in a first type of tube (e.g., a 15mm hot air tube), a 100k thermistor may be provided in a second type of tube (e.g., a 19mm hot air tube), and an open circuit may be provided in a third type of tube (e.g., a passive air tube without a heating element). The different resistance values provided by the sensors 6500 may allow the processing circuitry 6400 to determine the type of connected tube and which control parameters to use for operation of the RPT device 4000. Tube detection may be applied to the present technical disclosure using tube detection as described in U.S. provisional application 62/835,094 filed on 2019, 4 and 17, the contents of which are incorporated herein by reference in their entirety.

5.7.2 four-pin three-wire mark

Because the use of certain thermistors may provide a more accurate measurement of the temperature in air delivery tube 4170, certain example embodiments provide for identifying the air delivery tube type without the use of sensors having different characteristics (e.g., resistance). In one example, a 10K thermistor may be used in a different air delivery tube 4170 to provide a more accurate in-tube temperature measurement than a 100K thermistor.

Fig. 5E and 5F show schematic views of the air delivery tube 4170 connected to the RPT device 4000, where one of the sensor lines is not coupled to the sensor 6500. Sensor 6500 shown in fig. 5E and 5F may have similar parameters to those of sensor 6500 shown in fig. 5D. In one example, the sensor 6500 in fig. 5D, 5E, and 5F may be a 10k thermistor.

In fig. 5E and 5F, sensor 6500 is coupled to only one of the sensor wire and the heater wire. The sensor 6500 can be coupled to the one or more heating wires via a heating element, or directly coupled to the heating wires via a connection in the tube connector 6300 and bypassing a heating element in the one or more heating wires. In one example, the sensor 6500 may be coupled to one of the sensor wires, and the pin in the tube connector 6300 is coupled to the ground of the heater tube control circuit.

Different air delivery tube types may be specified by connecting sensor 6500 to different sensor lines from the plurality of sensor lines (two sensor lines are shown, but more may be included). For example, a first tube type (e.g., 15mm hot air tube) may be specified by coupling sensor 6500 to sensor line 2 and heater line, and a second tube type (e.g., 19mm hot air tube) may be specified by coupling sensor 6500 to sensor line 1 and heater line.

In the examples shown in fig. 5E and 5F, the contact assembly 6200 of the RPT device 4000 may comprise a 4-pin connection, while the tube connector 6300 may comprise a 3-pin connection. Different ways in which a lower number of pins in the air delivery tube 4170 are connected to a higher number of pins in the RPT device 4000 may be used to distinguish between different air delivery tubes 4170. In these examples, air delivery tube 4170 may include 3 wires (i.e., two for the heating element and one for sensor 6500) that run in the tube to the tube end coupled to patient interface 3000. In some examples, additional pins may be provided in the tube connector 6300 that do not electrically couple with any components in the air delivery tube. In other examples, the tube connector 6300 may not include an additional electrical pin (e.g., a fourth pin).

The cartridge detection circuit may determine the type of air delivery tube 4170 coupled to the RPT device 4000 by measuring the presence and/or absence of a signal on the pins of the contact assembly 6200. If there is no signal on the sensor line 1, the heater pipe detection circuit may identify the first type of air delivery pipe. If there is no signal on the sensor line 2, the heater pipe detection circuit may identify the second type of air delivery pipe.

In another example, a signal is present on the sensor wire 2 and the heater tube detection circuit may then identify the first type of air delivery tube. The heater-pipe detection circuit may identify the second type of air delivery pipe if a signal is present on the sensor line 1.

In some examples, the absence of a signal on two sensor lines may indicate that an air delivery tube is not connected to the RPT device 4000, or that a third type of air delivery tube (e.g., a non-heated tube) is coupled to the RPT device 4000.

Fig. 5G and 5H show schematic diagrams of the air delivery tube 4170 connected to the RPT device 4000, where the signal measured by the detection line is used to identify the type of air delivery tube 4170 coupled to the RPT device 4000. In fig. 5G and 5H, the heating elements in the air delivery tube 4170 are coupled with the heating wires in the RPT device 4000 by connections in the tube connector 6300, and the sensors 6500 are coupled with the sensor wires in the RPT device 4000 by connections in the tube connector 6300. The heating control circuitry in the RPT device 4000 may provide power to the heating elements in the air delivery tube 4170 through a heater wire and ground. The control circuit may determine the temperature in air delivery tube 4170 by measuring a signal from sensor 6500 that passes through a sensor line and ground.

The heat pipe detection circuit may determine the air delivery tube type based on signals received via the detection lines in the contact assembly 6200. As shown in fig. 5G, a first tube type (e.g., 15mm hot air tube) may be specified by the absence of an electrical connection (or pin) in the tube connector 6300 to a test line in the contact assembly 6200. As shown in fig. 6H, a second tube type (e.g., 19mm hot air tube) may be designated by pins in a tube connector 6300, which tube connector 6300 is electrically connected by a detectable electrical connection 6350 (e.g., in a cannula balloon). Electrical connection 6350 may include, for example, a planar short, a resistive connection, a shunt, an asymmetric (e.g., diode type), or an active signal. As shown in fig. 5H, electrical connections 6350 may be provided between the sensing wires and the ground terminals of the contact assemblies 6200 and the tube connectors 6300.

The heater tube detection circuit may determine the type of air delivery tube 4170 coupled to the RPT device 4000 by measuring the presence and/or absence of circuit components on the detection line of the contact assembly 6200. For example, a voltage may be applied to the sensing line to determine whether there is a current via a component coupled between the sensing line and ground. If there is no signal on the detection line (as shown in FIG. 5G), the heater pipe detection circuit may identify the first type of air delivery tube. If a signal is present on the detection line (as shown in FIG. 5H), the heater-tube detection circuit may identify the second type of air delivery tube.

In some examples, different types of electrical connections 6350 (e.g., different values of resistive elements) may be used to further distinguish between different types of air delivery tubes, and the heat pipe detection circuit may determine the type of pipe based on the signal received via the detection line.

In another example, when a signal is present on the sensor wire 2, then the heater pipe detection circuit may identify a first type of air delivery pipe. When a signal is present on the sensor line 1, the heater-pipe detection circuit can identify the second type of air delivery pipe.

The cartridge detection circuit may determine the type of air delivery tube 4170 coupled to the RPT device 4000 by determining whether there is an open circuit or a closed circuit on a circuit that includes the detection wire and one of the other connections (e.g., one of the heater wires). The first type of air delivery tube may be identified when the circuit is open and the second type of air delivery tube may be identified when the circuit is closed (e.g., due to a resistor or shunt coupling the sensing wire to one of the other connections in the air delivery tube 4170).

Air delivery tube identification may be performed based on signals received from sensor wires and/or detection wires in hardware and/or software. In some examples, the hardware and/or software may be configured to perform tube identification at startup of the RPT device 4000, at connection of an air duct to the RPT device 4000, periodically during operation of the RPT device 4000 and/or at start of operation of the RPT device 4000.

FIG. 5I illustrates an example heat pipe detection circuit in accordance with one form of the present technique. The heater-tube detection circuit shown in fig. 5I may be used to identify the air delivery tube type using the identification circuits provided in fig. 5E and 5F.

The comparator 5290 can be coupled to the sensor lines and provide an output signal to a controller 5250, which controller 5250 is configured to control the heating element 5240, the heated air circuit 4171, and/or other components of the RPT device 4000 based on the determined tube type and data received from the sensor 5210. Sensor wires 1 and 2 may be coupled to a comparator configured to compare signals received via the sensor wires. If the signal on sensor line 1 is lower than the signal on sensor line 2 (configuration shown in fig. 5E), the comparator may output a first value (e.g., zero), and if the signal on sensor line 2 is lower than the signal on line 1 (configuration shown in fig. 5F), the comparator may output a second value (e.g., one). In this example, a digital output of 1 or 0 may distinguish between the two tube types and indicate the type of air delivery tube 4170 coupled to the RPT device 4000. In some examples, comparator 5290 may be further configured to determine when the signal on the sensor line is equal to indicate a third type of air delivery tube 4170 or the absence of an air delivery tube 4170. The third type of air delivery tube may correspond to an air delivery tube without a heating element and/or sensor.

FIG. 5J illustrates an example heat pipe detection circuit in accordance with another form of the present technique. The cartridge detection circuit shown in fig. 5J may be used to identify the air delivery tube type using the identification circuits provided in fig. 5G and 5H.

The comparator 5292 can be coupled to the sensing line and provide an output signal to the controller 5250, the controller 5250 configured to control the heating element 5240, the heated air circuit 4171 and/or other components of the RPT device 4000 based on the determined tube type and data received from the sensors 5210. The detection lines may be coupled to a comparator configured to compare a signal received via the detection lines to a reference value (e.g., ground or a reference voltage). The comparator 5292 may output a first value (e.g., 1) if the signal on the detection line is higher than the reference value (the configuration shown in fig. 5H), and may output a second value (e.g., 0) if the signal on the detection line is equal to or lower than the reference value (the configuration shown in fig. 5G). In this example, a digital output of 1 or 0 may indicate the type of air delivery tube 4170 coupled to the RPT device 4000.

While the above examples of the present technology have been described with reference to three-wire or four-wire systems and connectors having three or pins in the connector, the examples are not limited thereto. Examples of the present techniques may be applied to systems having other numbers of wires (e.g., two wires, three wires, or five or more wires) and/or other numbers of pins. For example, additional sensor lines may be included in the RPT device 4000 to distinguish between a large number of air delivery tube types.

5.8 respiratory waveforms

Fig. 6A shows a model typical respiration waveform of a person while sleeping. The horizontal axis is time and the vertical axis is respiratory flow. While the parameter values may vary, a typical breath may have the following approximation: tidal volume Vt 0.5L, inspiration time Ti 1.6s, peak inspiration flow Qpeak 0.4L/s, expiration time Te 2.4s, and peak expiration flow Qpeak-0.5L/s. The total duration of the breath Ttot is about 4 s. Humans typically breathe at about 15 Breaths Per Minute (BPM) with vents of about 7.5L/min. Typical duty cycles, the ratio of Ti to Ttot, is about 40%.

FIG. 6B shows selected polysomnography channels (pulse oximetry, flow, chest movement, and abdominal movement) of a patient during non-REM sleep breathing, which is typically treated with auto-PAP therapy over a period of about 90 seconds, with about 34 breaths, and an interface pressure of about 11cmH₂And O. Apical channel display pulse oximetry (oxygen saturation or SpO)₂) The scale has a saturation range from 90% to 99% in the vertical direction. The patient maintained about 95% saturation throughout the period shown. The second channel shows a quantitative respiratory airflow, with a scale from-1 to +1LPS in the vertical direction, and positive inspiration. Chest and abdomen movements are shown in the third and fourth channels.

Figure 6C shows polysomnography of a patient before treatment. There are 11 signal channels with a horizontal span of 6 minutes from top to bottom. The first two channels are EEG (electroencephalograms) from different scalp locations. Periodic spikes in the second EEG represent cortical arousalsAnd related activities. The third pathway down is submental EMG (electromyography). Increased near the time of arousal indicates genioglossus muscle recruitment. The fourth and fifth channels are EOG (electro-oculogram). The sixth channel is an electrocardiogram. The seventh channel shows pulse oximetry (SpO)₂) It has a repetitive desaturation from about 90% to below 70%. The eighth channel is the flow of breathing gas using a nasal cannula connected to a differential pressure transducer. Repeated apneas of 25 to 35 seconds alternated with resumed breathing bursts of 10 to 15 seconds, consistent with EEG arousals and increased EMG activity. The ninth channel represents movement of the chest and the tenth channel represents movement of the abdomen. The abdomen exhibits a gradual movement over the length of the apnea that causes arousals. Both become untidy during arousal due to the recovery of systemic movement during hyperpnoea. Thus, apnea is obstructive and the condition is severe. The lowest channel is a gesture, and in this example it does not show a change.

Fig. 6D shows patient flow data for a series of completely obstructive apneas the patient is experiencing. The duration of the recording is approximately 160 seconds. The flow rate ranges from about +1L/s to about-1.5L/s. Each apnea lasts about 10-15 seconds.

Figure 6E shows a scaled inspiratory portion of a breath in which the patient is experiencing low frequency inspiratory snoring.

Fig. 6F shows a scaled inspiratory portion of an example breath in which the patient is experiencing a flattened inspiratory flow limitation.

Fig. 6G shows a scaled inspiratory portion of a breath for which the patient is experiencing an example "tabletop" flattened inspiratory flow limitation.

Fig. 6H shows a scaled inspiratory portion of an example breath in which the patient is experiencing an "panda-ear" inspiratory flow limitation.

Fig. 6I shows a scaled inspiratory portion of an example breath in which the patient is experiencing a "chair" inspiratory flow limitation.

Fig. 6J shows a scaled inspiratory portion of an example breath in which the patient is experiencing a "reverse chair" inspiratory flow limitation.

Fig. 6K shows a scaled inspiratory portion of a breath for which the patient is experiencing an example "M-shaped" inspiratory flow limitation.

Fig. 6L shows a scaled inspiratory portion of a breath for which the patient is experiencing a severe "M-shaped" inspiratory flow limitation.

Fig. 6M shows patient data from a patient with tidal breathing. There are three channels: pulse oximetry (SpO)₂) (ii) a A signal indicative of flow rate; and chest movements. Data span six minutes. A pressure sensor connected to the nasal cannula is used to measure a signal representative of the flow. The patient exhibited an apnea of about 22 seconds and an hyperpnea of about 38 seconds. Higher frequency, low amplitude oscillations during apnea are cardiogenic.

Fig. 6N shows patient data for a patient with another example of cheyne-stokes respiration using the same three channels as in fig. 6M. Data span 10 minutes. The patient exhibited about 30 seconds of hyperpnea and about 30 seconds of hypopnea.

5.9 respiratory therapy mode

Various respiratory therapy modes may be implemented by the disclosed respiratory therapy system.

5.9.1 CPAP treatment

In some implementations of respiratory pressure therapy, the central controller 4230 sets the therapy pressure Pt according to therapy pressure equation (1) as part of the therapy parameter determination algorithm 4329. In one such implementation, amplitude a is also zero, so therapy pressure Pt (which represents the target value achieved by interface pressure Pm at the present moment) is equal to base pressure P throughout the respiratory cycle₀. Such practices are generally grouped under the heading of CPAP therapy. In such implementations, the therapy engine module 4320 need not determine the phase Φ or the waveform template Π (Φ).

In CPAP treatment, the base pressure P₀May be hard coded or manually entered into the RPT device 4000. Alternatively, the central controller 4230 may repeatedly calculate the base pressure P₀As a function of an indicator or measure of sleep disordered breathing returned by a corresponding algorithm in therapy engine module 4320, such as one or more of flow limitation, apnea, hypopnea, patency, and snoring. This option is sometimes referred to as APAP therapy.

FIG. 4E is a flowchart illustrating a method 4500 performed by central controller 4230 for continuously calculating a base pressure P as part of an APAP therapy implementation of therapy parameter determination algorithm 4329 when pressure support A equals zero₀。

The method 4500 begins at step 4520, and at step 4520 the central controller 4230 compares the measure of the presence of apnea/hypopnea to a first threshold and determines whether the measure of the presence of apnea/hypopnea has exceeded the first threshold for a predetermined period of time, thereby indicating that apnea/hypopnea is occurring. If so, method 4500 proceeds to step 4540; otherwise, the method 4500 proceeds to step 4530. At step 4540, central controller 4230 compares the measure of airway patency to a second threshold. If the measure of airway patency exceeds a second threshold, indicating that the airway is open, then the detected apnea/hypopnea is deemed central, and the method 4500 proceeds to step 4560; otherwise, the apnea/hypopnea is considered obstructive and method 4500 proceeds to step 4550.

At step 4530, the central controller 4230 compares the measure of flow restriction to a third threshold. If the measure of flow restriction exceeds the third threshold, indicating that inspiratory flow is restricted, then the method 4500 proceeds to step 4550; otherwise, the method 4500 proceeds to step 4560.

At step 4550, the central controller 4230 sets the base pressure P₀The predetermined pressure increase Δ P is increased as long as the generated treatment pressure Pt does not exceed the maximum treatment pressure Pmax. In one implementation, the predetermined pressure increase Δ P and the maximum treatment pressure Pmax are each 1cmH₂O and 25cmH₂And O. In other implementations, the pressure increase Δ P may be as low as 0.1cmH₂O and up to 3cmH₂O, or as low as 0.5cmH₂O and up to 2cmH₂And O. In other implementations, the maximum treatment pressure Pmax can be as low as 15cmH₂O and up to 35cmH₂O, or as low as 20cmH₂O and up to 30cmH₂And O. The method 4500 then returns to step 4520.

In step 4560, the central controller 4230 sets the base pressure P₀By a reduction amount, provided that the base pressure P is reduced₀Does not fall below a minimum treatment pressure Pmin. The method 4500 then returns to step 4520. In one implementation, the amount of reduction is in combination with P₀The value of Pmin is proportional so that P, without any detected event, is such that P₀The decrease to the minimum treatment pressure Pmin is exponential. In one implementation, the proportionality constant is set such that P₀Is 60 minutes and the minimum treatment pressure Pmin is 4cmH₂And O. In other embodiments, the time constant τ may be as low as 1 minute and as high as 300 minutes, or as low as 5 minutes and as high as 180 minutes. In other implementations, the minimum treatment pressure Pmin can be as low as 0cmH₂O is as high as 8cmH₂O, or as low as 2cmH₂O is as high as 6cmH₂And O. Alternatively, P₀May be predetermined, so that in the absence of any detected event, P₀The decrease to the minimum treatment pressure Pmin is linear.

5.9.2 Bi-level treatment

In other implementations of this form of the present technique, the value of amplitude a in equation (1) may be positive. This is referred to as bi-level therapy because when determining the treatment pressure Pt using equation (1) with positive amplitude a, the treatment parameter determination algorithm 4329 oscillates the treatment pressure Pt between two values or levels in synchronization with the spontaneous respiratory effort of the patient 1000. That is, based on the above-described typical waveform template Π (Φ, t), the treatment parameter determination algorithm 4329 increases the treatment pressure Pt to P at the beginning or during or at inspiration₀+ A (called IPAP) and reducing the treatment pressure Pt to the base pressure P at or during the beginning of expiration₀(referred to as EPAP).

In some forms of bi-level therapy, IPAP is the treatment pressure with the same purpose as the treatment pressure in the CPAP treatment mode, and EPAP is IPAP minus amplitude A, which has a "small" value (a few cmH)₂O), sometimes referred to as Expiratory Pressure Relief (EPR). This form is sometimes referred to as CPAP therapy using EPR, which is generally considered to be more direct CPAP therapy than direct CPAP therapyThe treatment is more comfortable. In CPAP therapy using EPR, both IPAP and EPAP may be hard coded or constant values manually entered into the RPT device 4000. Alternatively, the treatment parameter determination algorithm 4329 may repeatedly calculate IPAP and/or EPAP during CPAP with EPR. In this alternative, the treatment parameter determination algorithm 4329 is programmed to match the base pressure P in APAP treatment described above₀In a similar manner, EPAP and/or IPAP are repeatedly calculated as a function of the indicators or measurements of sleep disordered breathing returned by the corresponding algorithm in therapy engine module 4320.

In other forms of bi-level therapy, amplitude a is large enough that RPT device 4000 performs some or all of the work of breathing of patient 1000. In this form of treatment, known as pressure support ventilation, the amplitude a is referred to as pressure support or oscillation. In pressure support ventilation therapy, IPAP is the base pressure P₀With pressure support A, EPAP is base pressure P₀。

In some forms of pressure support ventilation therapy, referred to as fixed pressure support ventilation therapy, the pressure support A is fixed at a predetermined value, e.g., 10cmH₂And O. The predetermined pressure support value is a setting of the RPT device 4000 and may be set, for example, by hard coding during configuration of the RPT device 4000 or by manual input through the input device 4220.

In other forms of pressure support ventilation therapy, broadly referred to as servoventilation, the therapy parameter determination algorithm 4329 takes as input some currently measured or estimated parameter of the respiratory cycle (e.g., the currently measured venture of ventilation) and a target value for that respiratory parameter (e.g., the target value for ventilation Vtgt), and repeatedly adjusts the parameters of equation (1) to bring the current measurement of the respiratory parameter close to the target value. In a form of servo ventilation known as Adaptive Servo Ventilation (ASV), which has been used to treat CSR, the breathing parameter is ventilation and the target ventilation Vtgt is calculated by the target ventilation determination algorithm 4328 from a typical recent ventilation Vtyp, as described above.

In some forms of servoventilation, the treatment parameter determination algorithm 4329 applies a control method to repeatedly calculate the pressure support a in order to bring the current measurement of the breathing parameter close to the target value. One such control method is proportional-integral (PI) control. In one implementation of PI control, for ASV modes where the target ventilation Vtgt is set to be slightly less than the typical recent ventilation Vtyp, the pressure support A is repeatedly calculated as:

A＝G∫(Vent-Vtgt)dt (2)

where G is the gain of the PI control. A larger gain G value may result in positive feedback in the therapy engine module 4320. A smaller gain G value may allow for some residual untreated CSR or central sleep apnea. In some implementations, the gain G is fixed at a predetermined value, e.g., -0.4cmH₂O/(L/min)/sec. Alternatively, the gain G may vary between treatment sessions, becoming smaller starting from one session and increasing from one session to another until a value is reached that substantially eliminates CSR. Conventional means for retrospectively analyzing parameters of a treatment session to assess the severity of CSR during the treatment session may be employed in such implementations. In other implementations, the gain G may vary based on the difference between the current measured Vent of ventilation and the target ventilation Vtgt.

Other servo ventilation control methods that may be applied by the therapy parameter determination algorithm 4329 include proportional (P), proportional-derivative (PD), and proportional-integral-derivative (PID).

The value of the pressure support a calculated via equation (2) may be clipped to a range defined as [ Amin, Amax ]. In this implementation, pressure support a is located at a minimum pressure support Amin by default until the measure of current ventilation Vent falls below the target ventilation Vtgt, at which point a begins to increase, falling back to Amin only when Vent again exceeds Vtgt.

The pressure support limits Amin and Amax are settings of the RPT device 4000, for example, set by hard coding during configuration of the RPT device 4000 or manual input through the input device 4220.

In the pressure support ventilation therapy mode, EPAP is the base pressure P₀. With base pressure P in CPAP treatment₀Likewise, EPAP may be a constant value specified or determined during titration. Such a constant EPAP may be installed, for example, by configuring the RPTHard coding during setting 4000 or manual input through the input device 4220. This alternative is sometimes referred to as fixed-EPAP pressure support ventilation therapy. During a titration session, a clinician may perform a titration of the EPAP of a given patient with the help of the PSG, with the aim of preventing obstructive apneas, thereby maintaining an open airway for pressure support ventilation therapy, in a manner similar to the baseline pressure P in constant CPAP therapy₀Titration.

Alternatively, the treatment parameter determination algorithm 4329 may repeatedly calculate the base pressure P during pressure support ventilation therapy₀. In such implementations, the therapy parameter determination algorithm 4329 repeatedly calculates EPAP as a function of an indicator or measure of sleep disordered breathing returned by a corresponding algorithm in the therapy engine module 4320, such as one or more of flow limitation, apnea, hypopnea, patency, and snoring. Because the continuous calculation of EPAP is similar to the clinician's manual adjustment of EPAP during an EPAP titration, this process is sometimes referred to as auto-titration of EPAP, and the treatment mode is referred to as auto-titration of EPAP pressure support ventilation therapy or auto-EPAP pressure support ventilation therapy.

5.9.3 high flow therapy

In other forms of respiratory therapy, the pressure of the airflow is not as controlled as respiratory pressure therapy. In contrast, central controller 4230 controls pressure generator 4140 to deliver a flow of gas whose device flow Qd is controlled to a therapeutic or target flow Qtgt that is generally positive throughout the patient's respiratory cycle. These modalities are typically grouped under the heading of flow therapy. In flow therapy, the treatment flow rate Qtgt may be a constant value hard coded or manually input to the RPT device 4000. If the treatment flow Qtgt is sufficient to exceed the peak inspiratory flow of the patient, the treatment is often referred to as High Flow Therapy (HFT). Alternatively, the therapeutic flow may be a curve qtgt (t) that varies with the respiratory cycle.

5.10 glossary

For the purposes of this technical disclosure, one or more of the following definitions may apply in certain forms of the present technology. In other forms of the present technology, alternative definitions may be applied.

5.10.1 overview

Air: in some forms of the present technology, air may be considered to mean atmospheric air, and in other forms of the present technology, air may be considered to mean some other combination of breathable gases, such as oxygen-enriched atmospheric air.

Environment: in certain forms of the present technology, the term environment may have the following meanings (i) outside of the treatment system or patient, and (ii) directly surrounding the treatment system or patient.

For example, the ambient humidity relative to the humidifier may be the humidity of the air immediately surrounding the humidifier, such as the humidity in a room where the patient sleeps. Such ambient humidity may be different from the humidity outside the room where the patient sleeps.

In another example, the ambient pressure may be a pressure directly around or outside the body.

In some forms, ambient (e.g., acoustic) noise may be considered to be the background noise level in the room in which the patient is located, in addition to noise generated by, for example, the RPT device or emanating from the mask or patient interface. Ambient noise may be generated by sound sources outside the room.

Automatic Positive Airway Pressure (APAP) therapy: CPAP therapy, in which the treatment pressure is automatically adjustable between a minimum limit and a maximum limit, for example, varying with each breath, depending on whether an indication of an SBD event is present.

Continuous Positive Airway Pressure (CPAP) therapy: respiratory pressure therapy, wherein the therapeutic pressure is substantially constant over the patient's respiratory cycle. In some forms, the pressure at the entrance of the airway will be slightly higher during exhalation and slightly lower during inhalation. In some forms, the pressure will vary between different respiratory cycles of the patient, for example increasing in response to detecting an indication of partial upper airway obstruction and decreasing in the absence of an indication of partial upper airway obstruction.

Flow rate: volume (or mass) of air delivered per unit time. Flow may refer to an instantaneous quantity. In some cases, the reference to flow will be a reference to a scalar quantity, i.e. a quantity having only a magnitude. In other cases, the reference to flow will be a reference to a vector, i.e. a quantity having both a magnitude and a direction. The traffic may be given by the symbol Q. The 'flow rate' is sometimes abbreviated simply as 'flow' or 'air flow'.

In the example of patient breathing, the flow may be nominally positive for the inspiratory portion of the patient's breathing cycle, and thus may be negative for the expiratory portion of the patient's breathing cycle. The device flow rate Qd is the flow rate of air exiting the RPT device. Total flow Qt is the flow of air and any supplemental gas to the patient interface via the air circuit. The ventilation flow Qv is the flow of air exiting the vent to allow washout of exhaled gas. Leak flow Ql is the leak flow from the patient interface system or elsewhere. The respiratory flow Qr is the flow of air received into the respiratory system of the patient.

Flow treatment: respiratory therapy involves delivering a flow of air to the entrance of the airway at a controlled flow, called the therapeutic flow, which is usually positive throughout the patient's respiratory cycle.

Humidifier: the term humidifier will be considered to refer to a humidification apparatus constructed and arranged or configured with a physical structure capable of providing a therapeutically beneficial amount of water (H) to a flow of air₂O) vapor to improve the medical respiratory condition of the patient.

And (3) leakage: word leaks will be considered to be an undesirable flow of air. In one example, leaks may occur due to an incomplete seal between the mask and the patient's face. In another example, the leak may occur in a swivel elbow to the surrounding environment.

Noise, conduction (acoustic): conductive noise in this document refers to noise that is brought to the patient through a pneumatic path, such as the air circuit and patient interface and the air therein. In one form, the conducted noise may be quantified by measuring the sound pressure level at the end of the air circuit.

Noise, radiation (acoustics): radiation noise in this document refers to noise brought to the patient by ambient air. In one form, the radiated noise may be quantified by measuring the acoustic power/pressure level of the object in question according to ISO 3744.

Noise, ventilation (acoustics): ventilation noise in this document refers to noise generated by air flow through any vent, such as a vent of a patient interface.

The patients: a person, whether or not they have a respiratory disorder.

Pressure: force per unit area. Pressure can be expressed in units of ranges, including cmH₂O、g-f/cm²Hectopascal. 1cmH₂O is equal to 1g-f/cm²And about 0.98 hectopa (1 hectopa 100Pa 100N/m)²1 mbar to 0.001 atm). In this specification, unless otherwise stated, the pressure is in cm H₂O is given in units.

The pressure in the patient interface is given by the symbol Pm and the therapeutic pressure is given by the symbol Pt, which represents the target value achieved by the interface pressure Pm at the present moment.

Respiratory Pressure Therapy (RPT): the air supply is applied to the airway inlet at a therapeutic pressure that is typically positive relative to atmosphere.

A breathing machine: a mechanism that provides pressure support to the patient to perform some or all of the respiratory work.

5.10.1.1 Material

Silicone or silicone elastomer: and (3) synthesizing rubber. In the present specification, reference to silicone refers to Liquid Silicone Rubber (LSR) or Compression Molded Silicone Rubber (CMSR). One form of commercially available LSR is SILASTIC (included in the range of products sold under this trademark), manufactured by Dow Corning corporation (Dow Corning). Another manufacturer of LSRs is Wacker group (Wacker). Unless otherwise specified to the contrary, exemplary forms of LSR have a shore a (or type a) indentation hardness in the range of about 35 to about 45 as measured using ASTM D2240.

Polycarbonate (C): is a thermoplastic polymer of bisphenol a carbonate.

5.10.1.2 mechanical Properties

Rebound resilience: the ability of a material to absorb energy when elastically deformed and release energy when unloaded.

Elasticity: substantially all of the energy will be released upon unloading. Including, for example, certain silicones and thermoplastic elastomers.

Hardness: the ability of the material itself to resist deformation (described, for example, by young's modulus or indentation hardness scale measured on standardized sample dimensions).

"soft" materials may include silicone or thermoplastic elastomer (TPE) and may be easily deformed, for example, under finger pressure.

"hard" materials may include polycarbonate, polypropylene, steel, or aluminum, and may not readily deform, for example, under finger pressure.

Stiffness (or rigidity) of a structure or component: the ability of a structure or component to resist deformation in response to an applied load. The load may be a force or a moment, such as compression, tension, bending or torsion. The structure or component may provide different resistance in different directions. The inverse of stiffness is flexibility.

Flexible structures or components: a structure or component that will change shape (e.g., bend) when allowed to support its own weight for a relatively short period of time, e.g., 1 second.

Rigid structures or components: a structure or component that does not substantially change shape when subjected to loads typically encountered in use. An example of such a use may be, for example, at about 20 to 30cmH₂Under the load of the pressure of O, the patient interface is disposed and maintained in a sealing relationship with the entrance to the patient's airway.

As an example, the I-beam may include a different bending stiffness (resisting bending loads) in a first direction than in a second orthogonal direction. In another example, the structure or component may be soft in a first direction and rigid in a second direction.

5.10.2 respiratory cycle

And (3) apnea: according to some definitions, an apnea is considered to occur when the flow rate falls below a predetermined threshold for a period of time (e.g., 10 seconds). Obstructive apnea is considered to occur when even the patient is struggling that some obstruction of the airway does not allow air to flow. Central apnea is considered to occur when apnea is detected due to a reduction in or absence of respiratory effort despite the airway being open (patent). Mixed apneas are considered to occur when a reduction or absence of respiratory effort coincides with an obstructed airway.

Breathing frequency: the rate of spontaneous breathing of a patient, which is typically measured in breaths per minute.

Duty ratio: the ratio of the inspiration time Ti to the total breath time Ttot.

Effort (breathing): spontaneous breathers attempt to breathe.

Expiratory portion of the respiratory cycle: the period from the start of expiratory flow to the start of inspiratory flow.

And (3) flow limitation: flow limitation will be considered a condition in the patient's breathing in which an increase in the patient's effort does not result in a corresponding increase in flow. Where flow limitation occurs during the inspiratory portion of the respiratory cycle, it may be described as inspiratory flow limitation. Where flow limitation occurs during the expiratory portion of the breathing cycle, it may be described as expiratory flow limitation.

Type of flow restriction inspiratory waveform:

(i) flattening: with a rise followed by a relatively flat portion followed by a fall.

(ii) M-shape: there are two local peaks, one at the leading edge, one at the trailing edge, and a relatively flat portion between the two peaks.

(iii) A chair shape: with a single local peak at the leading edge followed by a relatively flat portion.

(iv) Inverted chair shape: with a relatively flat portion followed by a single local peak at the trailing edge.

Hypopnea: according to some definitions, a hypopnea will be considered a reduction in flow, rather than a cessation of flow. In one form, a hypopnea may be considered to occur when the flow rate decreases below a threshold rate for a period of time. Central hypopneas are considered to occur when a hypopnea is detected due to a reduction in respiratory effort. In one form of adult, any of the following may be considered hypopneas:

(i) patient breathing decreased by 30% for at least 10 seconds plus associated 4% desaturation;

(ii) the patient's breathing is reduced (but less than 50%) for at least 10 seconds with associated desaturation or arousal of at least 3%.

Hyperpnea: the flow rate increases to a level higher than normal.

Inspiratory portion of the respiratory cycle: the period of time from the beginning of inspiratory flow to the beginning of expiratory flow is considered the inspiratory portion of the respiratory cycle.

Patency (airway): the degree to which the airway is open or the degree to which the airway is open. The open airway is open. Airway patency may be quantified, e.g., a value of (1) open and a value of zero (0) closed (occluded).

Positive End Expiratory Pressure (PEEP): the above-atmospheric pressure present in the end-tidal lungs.

Peak flow (Qpeak): the maximum value of flow during the inspiratory portion of the respiratory flow waveform.

Respiratory flow, patient air flow, respiratory air flow (Qr): these terms may be understood to refer to an estimation of respiratory flow by the RPT device, as opposed to "true respiratory flow" or "true respiratory flow", which is the actual respiratory flow experienced by the patient, typically expressed in liters per minute.

Tidal volume (Vt): when no additional effort is applied, the volume of air inhaled or exhaled during normal breathing. In principle, the inspiratory volume Vi (volume of inhaled air) is equal to the expiratory volume Ve (volume of exhaled air), so a single tidal volume Vt can be defined as being equal to either quantity. In practice, tidal volume Vt is estimated as some combination, e.g., an average, of inspiratory volume Vi and expiratory volume Ve.

(inhalation) time (Ti): the duration of the inspiratory portion of the respiratory flow waveform.

(expiration) time (Te): the duration of the expiratory portion of the respiratory flow waveform.

(total) time (Ttot): the total duration between the start of the inspiratory portion of one respiratory flow waveform and the start of the inspiratory portion of a subsequent respiratory flow waveform.

Typical near term ventilation: the ventilation value around which the ventilation venture near-term value tends to cluster over some predetermined timescale is a measure of the central tendency of the ventilation near-term value.

Upper Airway Obstruction (UAO): including partial and total upper airway obstruction. This may be associated with a state of flow restriction where the flow increases only slightly, or even decreases, as the pressure difference across the upper airway increases (Starling impedance behavior).

Ventilation (Vent): a measure of the rate of gas exchanged by the respiratory system of the patient. The measure of ventilation may include one or both of inspiratory and expiratory flow (per unit time). When expressed as a volume per minute, this amount is commonly referred to as "ventilation per minute". Ventilation per minute is sometimes given simply as volume and is understood to be volume per minute.

5.10.3 air flow

Adaptive servo-ventilator (ASV): a servoventilator with variable, rather than fixed, target ventilation. The variable target ventilation may be learned from some characteristics of the patient (e.g., the patient's breathing characteristics).

The backup rate is as follows: if not triggered by spontaneous respiratory effort, a ventilator parameter is determined that is the minimum respiratory rate (usually expressed in breaths per minute) that the ventilator will deliver to the patient.

And (3) circulation: termination of the inspiratory phase of the ventilator. When a ventilator delivers a breath to a spontaneously breathing patient, at the end of the inspiratory portion of the breathing cycle, the ventilator is said to be cycling to stop delivering the breath.

Expiratory Positive Airway Pressure (EPAP): the ventilator will attempt to achieve the desired interface pressure at a given time.

End-expiratory pressure (EEP): the ventilator will attempt to achieve the desired interface pressure at the end of the expiratory portion of the breath. If the pressure waveform template Π (Φ) is zero at the end of expiration, i.e., when Φ is 1, Π (Φ) is 0, then the EEP is equal to EPAP.

Inspiratory Positive Airway Pressure (IPAP): the maximum desired interface pressure that the ventilator attempts to achieve during the inspiratory portion of the breath.

And (3) pressure support: a value indicating that the pressure increase during inspiration of the ventilator exceeds the pressure increase during expiration of the ventilator, and typically means the pressure difference between the maximum value during inspiration and the base pressure (e.g., PS IPAP-EPAP). In some cases, pressure support means the difference that the ventilator wants to achieve, not the difference that it actually achieves.

Servo-ventilator: a ventilator that measures patient ventilation has a target ventilation and adjusts the pressure support level to bring the patient ventilation to the target ventilation.

Spontaneous/timed (S/T): a mode of a ventilator or other device that attempts to detect the onset of spontaneous breathing in a patient. However, if the device fails to detect a breath within a predetermined period of time, the device will automatically initiate delivery of the breath.

Swinging: equivalent terms for pressure support.

Triggering: when a ventilator delivers a breath of air to a spontaneously breathing patient, it is said to be triggered to do so when the patient attempts to begin the respiratory portion of the breathing cycle.

5.10.4 patient interface

Anti-asphyxia valve (AAV): by opening to the atmosphere in a fail-safe manner, excessive patient CO is reduced₂Components or subcomponents of the mask system that risk rebreathing.

Bending the tube: an elbow is an example of a structure that directs the axis of an air stream traveling therethrough to change direction through an angle. In one form, the angle may be about 90 degrees. In another form the angle may be greater than or less than 90 degrees. The elbow may have an approximately circular cross-section. In another form, the elbow may have an elliptical or rectangular cross-section. In some forms, the elbow may rotate relative to the mating component, for example about 360 degrees. In some forms, the elbow may be removable from the mating component, for example, via a snap-fit connection. In some forms, the elbow may be assembled to the mating component via a one-time snap during manufacture, but cannot be removed by the patient.

A frame: a frame will be considered to mean a mask structure that carries tension loads between two or more attachment points to the headgear. The mask frame may be a non-airtight load bearing structure in the mask. However, some forms of mask frame may also be airtight.

Head cover: headgear will be considered to mean a form of positioning and stabilizing structure designed for use on the head. For example, the headgear may include a set of one or more support rods, straps, and reinforcements configured to position and hold the patient interface in a position on the patient's face for delivery of respiratory therapy. Some tethers are formed from soft, flexible, resilient materials, such as laminated composites of foam and fabric.

Film formation: a film will be understood to mean a typically thin element which preferably has substantially no resistance to bending, but which has resistance to stretching.

A plenum chamber: a mask plenum will be understood to mean that portion of a patient interface having a wall that at least partially encloses a volume of space that, in use, has air pressurized therein to above atmospheric pressure. The housing may form part of the wall of the mask plenum chamber.

Sealing: may refer to the noun form of the structure ("seal") or may refer to the verb form of the effect ("seal"). The two elements may be constructed and/or arranged to 'seal' or to effect 'sealing' therebetween without the need for a separate 'sealing' element itself.

A housing: the housing will be considered to mean a curved and relatively thin structure having a flexural, extensible and compressible stiffness. For example, the curved structural wall of the mask may be a shell. In some forms, the housing may be multi-faceted. In some forms, the housing may be air tight. In some forms, the housing may not be airtight.

A reinforcing member: a stiffener will be understood to mean a structural component designed to increase the resistance of another component to bending in at least one direction.

Supporting the rods: the support bar will be considered to be a structural component designed to increase the resistance of another component to compression in at least one direction.

Spindle (noun): a subassembly of components configured to rotate about a common axis, preferably independently, preferably at low torque. In one form, the swivel may be configured to rotate through an angle of at least 360 degrees. In another form, the swivel may be configured to rotate through an angle of less than 360 degrees. When used in the context of an air delivery conduit, the subassembly of components preferably comprises a pair of mating cylindrical conduits. There may be little or no air flow leaking from the spindle during use.

Ties (noun): a structure for resisting tensile forces.

And (4) air vents: (noun): structures that allow air flow from the mask interior or conduit to ambient air for clinically effective washout of exhaled air. For example, a clinically effective flush may involve a flow rate of about 10 liters per minute to about 100 liters per minute, depending on the mask design and treatment pressure.

5.11 other comments

A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the patent office document or records, but otherwise reserves all copyright rights whatsoever.

Unless the context clearly dictates otherwise and where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit, and any other stated or intervening value in that stated range, between the upper and lower limit of that range, is encompassed within the technology. The upper and lower limits of these intermediate ranges (which may independently be included in the intermediate ranges) are also encompassed within the technology, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the present technology.

Further, where one or more values are stated herein as being implemented as part of the technology, it is to be understood that such values may be approximate, and that such values may be used in any suitable significant digit to the extent that an actual technology implementation may permit or require it, unless otherwise stated.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this technology belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present technology, a limited number of exemplary methods and materials are described herein.

When a particular material is provided for use in constructing a component, obvious alternative materials having similar properties may be used as alternatives. Moreover, unless specified to the contrary, any and all components described herein are understood to be capable of being manufactured, and thus may be manufactured together or separately.

It must be noted that, as used herein and in the appended claims, the singular forms "a," "an," and "the" include their plural equivalents unless the context clearly dictates otherwise.

All publications mentioned herein are incorporated herein by reference in their entirety to disclose and describe the methods and/or materials which are the subject of those publications. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the technology is not entitled to antedate such disclosure by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates which may need to be independently confirmed.

The terms "comprising" and "including" should be understood as: refers to elements, components or steps in a non-exclusive manner, indicates that the referenced elements, components or steps may be present or utilized, or combined with other elements, components or steps that are not referenced.

The subject matter headings used in the detailed description are included for the convenience of the reader only and should not be used to limit subject matter found in the entire disclosure or claims. The subject matter headings should not be used to construe the scope of the claims or the limitations of the claims.

Although the technology herein has been described with reference to particular examples, it is to be understood that these examples are merely illustrative of the principles and applications of the technology. In some instances, terms and symbols may imply specific details that are not required to practice the techniques. For example, although the terms "first" and "second" may be used, unless otherwise specified, they are not intended to denote any order, but rather may be used to distinguish between different elements. Moreover, although process steps in a method may be described or illustrated in a sequential order, such a sequential order is not required. Those skilled in the art will recognize that such sequences may be modified and/or that aspects thereof may be performed simultaneously or even synchronously.

It is therefore to be understood that numerous modifications may be made to the illustrative examples and that other arrangements may be devised without departing from the spirit and scope of the present technology.

5.12 list of reference numerals

Claims (19)

1. An apparatus for humidifying a flow of breathable gas, comprising:

a processing circuit;

a humidifier configured to humidify the breathable gas;

an air delivery tube configured to deliver the humidified breathable gas to a patient interface, the air delivery tube including one or more heating elements extending along at least a portion of a length of the air delivery tube, a sensor configured to measure a characteristic of the humidified breathable gas in the air delivery tube, and a connector having a plurality of electrical tube contacts; and

a contact assembly comprising a plurality of electrical device contacts configured for electrically coupling the plurality of electrical tube contacts to the processing circuitry,

wherein the one or more heating elements and the sensor are coupled to the electrical tube contacts and the electrical tube contacts are adapted for electrically engaging only a portion of the electrical device contacts in an operating configuration of the device.

2. The apparatus of claim 1, wherein the processing circuitry is configured to control operation of the one or more heating elements and the humidifier based on signals received from the sensors, and to determine the type of the air delivery tube coupled to the apparatus based on which electrical apparatus contacts of the contact assembly are coupled to the electrical tube contacts in the operational configuration of the apparatus.

3. The device of claim 1, wherein the processing circuitry is configured to determine the type of the air delivery tube coupled to the device based on which electrical device contacts of the contact assembly are coupled to the electrical tube contacts in the operational configuration of the device.

4. The device of any one of claims 1 to 3, wherein the processing circuitry is configured to control operation of the one or more heating elements and/or the humidifier based on the determined type of air delivery tube.

5. The device of any one of claims 1-4, wherein the processing circuitry is configured to determine the type of the air delivery tube coupled to the device based on a lack of connection to the heating element and/or sensor through one or more electrical device contacts.

6. The device of any of claims 1-5, wherein the contact assembly includes only four electrical device contacts, a first pair of electrical device contacts configured to electrically couple to the one or more heating elements, and only one contact of a second pair of electrical device contacts configured to electrically couple to the sensor.

7. The device of any of claims 1-6, wherein the processing circuitry determines the type of the air delivery tube coupled to the device based on which of the second pair of electrical device contacts is coupled to the sensor.

8. The device of any of claims 1-7, wherein the contact assembly includes only four electrical device contacts, a first pair of the electrical device contacts configured to electrically couple to the one or more heating elements, and the processing circuit is configured to determine that a first type of air delivery tube is coupled to the device when a first contact of a second pair of the electrical device contacts is not coupled to the sensor, and to determine that a second type of air delivery tube is coupled to the device when a second contact of the second pair of electrical device contacts is not coupled to the sensor.

9. The device of any of claims 1-8, wherein the contact assembly includes only four electrical device contacts and the air delivery tube includes only three electrical tube contacts configured to couple to the electrical device contacts.

10. The device of any one of claims 1-9, wherein the processing circuitry is configured to determine the type of the air delivery tube coupled to the device based on which electrical device contact of the contact assembly is not coupled to the electrical tube contact.

11. An apparatus for humidifying a flow of breathable gas, comprising:

a processing circuit;

a humidifier configured to humidify the breathable gas;

an air delivery tube configured to deliver the humidified breathable gas to a patient interface, the air delivery tube including one or more heating elements extending along at least a portion of a length of the air delivery tube, a sensor configured to measure a characteristic of the breathable gas in the air delivery tube, and a connector having a plurality of electrical tube contacts; and

a contact assembly comprising a plurality of electrical device contacts configured for electrically coupling the plurality of electrical tube contacts to the processing circuitry in an operational configuration of the device,

wherein the one or more heating elements and the sensor are coupled to a set of electrical tube contacts configured for electrically coupling to corresponding electrical device contacts in an operational configuration of the device, and the processing circuitry is configured for determining the type of air delivery tube coupled to the device based on an electrical characteristic measured by the processing circuitry via another electrical device contact of the contact assembly.

12. The device of claim 10, wherein the processing circuitry is configured to control operation of the one or more heating elements and the humidifier based on signals received from the sensor.

13. The device of any of claims 11 or 12, wherein the measured characteristic comprises a voltage set based on a resistive element disposed in the air delivery tube and coupled to the other electrical device contact, and an electrical tube contact configured to electrically couple to a heating element.

14. The apparatus of any of claims 11 to 13, wherein the processing circuitry is configured to determine that a first type of air delivery tube is coupled to the apparatus when the measured characteristic indicates zero volts and to determine that a second type of air delivery tube is coupled to the apparatus when the measured characteristic indicates a voltage greater than zero.

15. The device of any of claims 11-14, wherein the air delivery tube comprises a resistor or shunt connected between a contact of the set of electrical tube contacts and an electrical tube contact configured to electrically couple to the other electrical device contact.

16. The apparatus of any of claims 11-15, wherein the processing circuitry is configured to control operation of the one or more heating elements and the humidifier based on the determined type of air delivery tube.

17. The device of any of claims 11-16, wherein the contact assembly includes only four electrical device contacts and the air delivery tube includes only three electrical tube contacts configured to couple to the electrical device contacts.

18. A respiratory therapy apparatus comprising:

a power source;

a processing system;

a pressure generator configured for generating a flow of breathable gas;

a humidifier configured for storing a supply of water for humidifying the breathable gas and comprising a first heating element configured for heating the supply of water;

an air delivery tube configured to deliver a humidified flow of breathable gas to a patient, the air delivery tube including a second heating element configured to heat the humidified breathable gas in the air delivery tube and a thermistor configured to generate a temperature signal indicative of a temperature of the humidified breathable gas in the air delivery tube;

a converter configured to generate a flow signal representative of a characteristic of the flow of breathable gas; and

a contact assembly configured for mechanically coupling the air delivery tube to the humidifier and electrically coupling a plurality of main contacts coupled to the processing system to a plurality of tube contacts coupled to the second heating element and the thermistor, wherein in an operational configuration of the respiratory therapy apparatus, only a portion of the main contacts are coupled to corresponding tube contacts;

the processing system is configured to:

determining which of the main contacts is coupled to the second heating element and the thermistor via the tube contact based on signal values received from the one or more main contacts;

determining a type of air delivery tube coupled to the humidifier based on the determination of which main contact is coupled to the second heating element and the thermistor; and

based on the determined tube type, flow signal, and temperature signal, determine (1) a first control signal for controlling the first heating element (2) a second control signal for controlling the second heating element, and (3) a third control signal for controlling the pressure generator.

19. The respiratory therapy apparatus of claim 18, wherein the contact assembly includes two main contacts and two additional main contacts, the two main contacts configured to electrically couple to two tube contacts coupled to the second heating element, the two additional main contacts configured to couple to two additional tube contacts, only one of the two additional tube contacts coupled to the thermistor, and the processing system is configured to determine the type of air delivery tube coupled to the humidifier based on which of the two additional main contacts is coupled to the thermistor via the tube contact.

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